Curable composition

ABSTRACT

The present invention has its object to provide a curable composition not containing any organotin type curing catalyst currently of concern because of the toxic feature thereof, or any volatile compound, excellent in curability and storage stability and, further, capable of providing cured products excellent in strength and elongation; the above object can be achieved by a curable composition which includes: an organic polymer (A) containing a hydrolyzable silyl group in a molecule; an amidine compound (B); and a compound (C) containing a sulfonyl group in a molecule.

TECHNICAL FIELD

The present invention relates to a curable composition comprising one ormore organic polymers having a silicon-containing group which has ahydroxyl group or hydrolyzable group bonded to a silicon atom and canform a siloxane bond to be crosslinked (hereinafter referred to as a“reactive silyl group”).

BACKGROUND ART

It is known that organic polymers containing at least one reactive silylgroup in the molecule have properties such that they are crosslinkedunder siloxane bond formation resulting from hydrolysis and otherreactions of the reactive silyl group due to moisture and the like, evenat room temperature, to give rubber-like cured products.

Among these reactive silyl group-containing polymers, those polymerswhich have a polyoxyalkylene type or polyisobutylene type main chainskeleton are disclosed in Patent Document 1, Patent Document 2 and thelike and have already been produced industrially and are in wide use insuch fields as sealants, adhesives and coatings.

For obtaining cured products from a curable composition including suchreactive silyl group-containing organic polymers, a silanol condensationcatalyst is used. Generally used as the silanol condensation catalystare organotin type catalysts having a carbon-tin bond such as dibutyltinbis(acetylacetonate) and dibutyltin dilaurate. In recent years, however,the toxicity of organotin type compounds have been pointed out anddevelopment of non-organotin catalysts has been desired.

Patent Document 3, Patent Document 4, Patent Document 5, Patent Document6 and Patent Document 7 disclose carboxylic acid tin salts and othercarboxylic acid metal salts as silanol condensation catalysts.

Patent Documents 3 to 7 further disclose that the addition of an aminecompound as a promoter to these catalysts results in improvedcurability. However, from the viewpoint of reduction in environmentalstress, substantially metal-free curing catalysts are desired and,Patent Document 8 discloses the combined use of an amine compound and acarboxylic acid for giving a metal-free silanol condensation catalyst.

It is publicly known that the combined use of an amine compound andother silanol condensation catalysts leads to improved curability.However, when the non-organotin type catalysts described in the patentsmentioned above are used, there arises a problem such that theadhesiveness of the cured products obtained is inferior as compared withthe use of organotin type catalysts.

There are disclosed almost no examples in which amine compounds are usedsingly as silanol condensation catalysts. Patent Document 9 discloses atechnology which comprises utilizing certain amine compounds known inthe art as silanol condensation catalysts and mentions1,8-diazabicylco[5.4.0]undecene-7 (DBU) and the like as the aminecompounds.

However, when the amine compounds described in Patent Document 9 areused as silanol condensation catalysts of the reactive silylgroup-containing organic polymers, some curable compositions exhibit nopractical curability. Furthermore, there are certain cases where thecured products obtained therefrom are inferior in adhesiveness althoughthe curable compositions exhibit practical curability.

Patent Document 10 discloses a technology which comprises usingbiguanide compounds, which constitute a group among amine compounds, assilanol condensation catalysts.

However, when the amine compounds described in Patent Document 10 areused as silanol condensation catalysts of the reactive silylgroup-containing organic polymers, some curable compositions areinferior in surface curability and depth curability at the early stageof curing.

Patent Document 10 discloses a method in which a biguanide compound(solid at room temperature) is dissolved in a plasticizer or an organicsolvent and then added. Upon use of the disclosed plasticizer, thereare, however, some cases where amidine compounds are precipitated due toinsufficient solubility, or the storage stability of a one-pack typecomposition is deteriorated due to moisture contained in theplasticizer. There also has been a problem that upon use of thedisclosed organic solvent, volatilization of the organic solvent bringsabout pollution of the work environment.

Patent Document 1: Japanese Kokai Publication S52-73998

Patent Document 2: Japanese Kokai Publication S63-6041

Patent Document 3: Japanese Kokai Publication H05-39428

Patent Document 4: Japanese Kokai Publication H09-12860

Patent Document 5: Japanese Kokai Publication 2000-313814

Patent Document 6: Japanese Kokai Publication 2000-345054

Patent Document 7: Japanese Kokai Publication 2003-206410

Patent Document 8: Japanese Kokai Publication H05-117519

Patent Document 9: WO 2004/022618

Patent Document 10: Japanese Kokai Publication 2005-248175

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a curablecomposition which includes a reactive silyl group-containing organicpolymer, does not contain, as a silanol condensation catalyst, anyorganotin type curing catalyst currently of concern because of the toxicfeature thereof, or any volatile compound, is excellent in curabilityand storage stability and, further, can provide cured products excellentin strength and elongation.

As a result of intensive investigations made by the present inventors tosolve such problems as mentioned above, the inventors found thefollowing and completed the present invention.

-   An amidine compound having a specific structure acts effectively as    a curing catalyst of a reactive silyl group-containing organic    polymer, and the amidine compound can be substituted for an    organotin type curing catalyst.-   A compound containing a sulfonyl group represented by —S(═O)₂— in a    molecule is effective in dissolving the above-mentioned amidine    compound having the specific structure.-   It is possible to control generation of VOC by selecting, as the    sulfonyl group-containing compound, a compound having a boiling    point of not lower than 200° C. at 760 mmHg, and consequently to    maintain a good work environment even upon use of the curable    composition in a room.-   When the solubility of the amidine compound is insufficient even    upon use of the sulfonyl group-containing compound, blending of a    silane coupling agent having an amino group leads to significant    improvement of solubility.-   Blending of the silane coupling agent having an amino group makes it    possible to remove moisture contained in the mixture which includes    the amidine compound and the sulfonyl group-containing compound, and    a curable composition obtained by mixing the above mixture with a    silyl group-containing organic polymer inhibits a rise in viscosity    during storage, and enables a long-term use thereof.

These findings also solve the following problem, as well as theabove-mentioned problem.

The curable composition including a reactive silyl group-containingorganic polymer is primarily employed as a one-pack typemoisture-curable composition.

The one-pack type moisture-curable composition used herein is obtainedby mixing a reactive silyl group-containing organic polymer with afiller, a plasticizer and the like, heating the mixture and/or reducingthe pressure thereon so as to remove moisture contained in the mixture,thereafter adding a silane coupling agent and a curing catalyst thereto,and putting the mixture obtained into an airtight container. When theone-pack type moisture-curable composition is taken out from thecontainer upon use thereof, curing is initiated by reaction withmoisture in the air.

However, there is a problem, that is, even when specific amidinecompounds used in the present invention, which are solid at roomtemperature, are added in the form of fine powder to the curablecomposition, the powder thereof is agglomerated and not sufficientlydispersed so that the amidine compounds are more likely to remain, in asmall mass, in the curable composition. There also remains a problemthat the cured products obtained may be inferior in tensile properties,such as strength and elongation at break.

That is, the present invention relates to the following (I) to (XIII):

-   (I). A curable composition which comprises:

100 parts by weight of an organic polymer (A) containing, in a molecule,a reactive silyl group represented by the formula: —SiR¹ _(n)X¹ _(3-n)(wherein the n R¹ groups each represent at least one kind selected fromthe group consisting of C₁₋₂₀ alkyl groups, C₆₋₂₀ aryl groups and C₇₋₂₀aralkyl groups, and the (3-n) X¹s are each independently either ahydroxyl group or a hydrolyzable group);

0.1 to 30 parts by weight of an amidine compound (B) represented by theformula (1):

R²N═CR³—NR⁴2   (1)

(wherein R², R³, and the two R⁴s are each independently a hydrogen atomor an organic group); and

0.1 to 100 parts by weight of a compound (C) containing, in a molecule,a sulfonyl group represented by the formula: —S(═O)₂—.

-   (II). The curable composition according to (I), wherein the amidine    compound (B) is dissolved and/or dispersed in the sulfonyl    group-containing compound (C), and the resultant product is mixed in    the reactive silyl group-containing organic polymer (A).-   (III). A curable composition which comprises:

a reactive silyl group-containing organic polymer (A);

an amidine compound (B);

a sulfonyl group-containing compound (C); and

a silane coupling agent (D).

-   (IV). The curable composition according to (III), wherein the    amidine compound (B) is dissolved and/or dispersed in the sulfonyl    group-containing compound (C) and the silane coupling agent (D), and    the resultant product is mixed in the reactive silyl    group-containing organic polymer (A).-   (V). The curable composition according to (III), wherein the amidine    compound (B) is dissolved and/or dispersed in the sulfonyl    group-containing compound (C), thereafter, the silane coupling    agent (D) is added to the resultant mixture, and dissolved and/or    dispersed, and the resultant product is mixed in the reactive silyl    group-containing organic polymer (A).-   (VI). The curable composition according to any one of (III) to (V),    wherein the silane coupling agent (D) contains an amino group in a    molecule.-   (VII). The curable composition according to any one of (I) to (VI),    wherein the main chain skeleton of the reactive silyl    group-containing organic polymer (A) is a polyoxyalkylene and/or    (meth)acrylate ester polymer.-   (VIII). The curable composition according to any one of (I) to    (VII), wherein the amidine compound (B) represented by the    formula (1) is a guanidine compound in which R³ in the formula (1)    is an organic group represented by —NR⁵ ₂ (wherein the two R⁵s are    each independently an organic group).-   (IX). The curable composition according to any one of (I) to (VIII),    wherein the amidine compound (B) contains an aryl group in a    molecule.-   (X). The curable composition according to any one of (I) to (IX),    wherein the sulfonyl group-containing compound (C) has a boiling    point of not lower than 200° C. at 760 mmHg.-   (XI). The curable composition according to any one of (I) to (X),    wherein 3 to 100% by weight of the reactive silyl group contained in    one molecule of the reactive silyl group-containing organic    polymer (A) is a silyl group represented by the formula: —SiX¹ ₃    (wherein the three X¹s are each independently either a hydroxyl    group or a hydrolyzable group).-   (XII). A sealant which comprises the curable composition according    to any one of (I) to (XI).-   (XIII). An adhesive which comprises the curable composition    according to any one of (I) to (XI).

The curable composition of the invention contains neither any organotincompound currently of concern because of the toxic feature thereof norany low volatile component that is a VOC generation source, andtherefore is superior in environmental compatibility. Improvement of thesolubility of a curing catalyst composed of the basic compound thatconventionally has difficulty in its uniform dispersion into acomposition makes it possible to uniformly disperse the curing catalystinto a composition, with the result that the cured products obtainedhave a smooth surface and excel in strength and elongation. Also, aone-pack type curable composition of the invention has no viscosity riseeven after storage, which allows for a favorable long-term use. When theone-pack type curable composition is taken out from a hermeticallypacked container, it reacts with moisture in the air and exhibits goodcurability.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, the present invention is described in detail.

The curable composition of the invention includes, as an essentialconstituent, a reactive silyl group-containing organic polymer (A).

The organic polymer (A) has, on an average, at least one reactive silylgroup per molecule. The reactive silyl group, so referred to herein, isan organic group containing a hydroxyl group or hydrolyzable group eachbound to a silicon atom. The reactive silyl group-containing organicpolymer (A) is crosslinked under siloxane bond formation as a result ofa reaction promoted by a silanol condensation catalyst.

There may be mentioned a group represented by the formula (2) as thereactive silyl group:

—SiR¹ _(n)X¹ _(3-n)   (2)

(wherein the n R¹ groups each represent at least one group selected fromamong C₁₋₂₀ alkyl groups, C₆₋₂₀ aryl groups and C₇₋₂₀ aralkyl groups,and the (3-n) X¹s are each independently either a hydroxyl group or ahydrolyzable group).

The curable composition of the present invention, which includes areactive silyl group-containing organic polymer (A) as the maincomponent, is better in compatibility with the curing catalyst, namelythe amidine compound (B), as compared with a composition which includes,as the main component, such an inorganic polymer aspolydimethylsiloxane, hence is preferred. The curable compositionincluding an organic polymer (A) is excellent in curability and thecured products obtained therefrom are characterized by excellentadhesiveness.

Further, for the same reasons, the organic polymer (A) preferably has amain chain skeleton containing at least one atom selected from among ahydrogen atom, a carbon atom, a nitrogen atom, an oxygen atom and asulfur atom.

The main chain skeleton of the organic polymer (A) is not particularlyrestricted but includes, polyoxyalkylene type polymers such aspolyoxyethylene, polyoxypropylene, polyoxybutylene,polyoxytetramethylene, polyoxyethylene-polyoxypropylene copolymers andpolyoxypropylene-polyoxybutylene copolymers; hydrocarbon type polymerssuch as ethylene-propylene type copolymers, polyisobutylene, copolymersof isobutylene and isoprene or the like, polychloroprene, polyisoprene,copolymers of isoprene or butadiene and acrylonitrile and/or styrene orthe like, polybutadiene and copolymers of isoprene or butadiene andacrylonitrile and styrene or the like, and hydrogenated polyolefinpolymers derived from these polyolefin type polymers by hydrogenation;polyester type polymers obtained by condensation of a dibasic acid suchas adipic acid and a glycol, or ring-opening polymerization of alactone(s); (meth)acrylate ester polymers obtained by radicalpolymerization of such a compound as ethyl (meth)acrylate and butyl(meth)acrylate; vinyl polymers obtained by radical polymerization ofsuch a compound as a (meth)acrylate ester compound, vinyl acetate,acrylonitrile and styrene; graft polymers obtained by polymerizing avinyl compound in such polymers as mentioned above; polysulfide typepolymers; polyamide type polymers such as polyamide 6 produced byring-opening polymerization of ε-caprolactam, polyamide 6.6 produced bypolycondensation of hexamethylenediamine and adipic acid, polyamide 6.10produced by polycondensation of hexamethylenediamine and sebacic acid,polyamide 11 produced by polycondensation of ε-aminoundecanoic acid,polyamide 12 produced by ring-opening polymerization ofε-aminolaurolactam, and copolymer polyamides composed of a plurality ofthe polyamides mentioned above; polycarbonate type polymers such aspolycarbonates produced by polycondensation of bisphenol A and carbonylchloride; diallyl phthalate type polymers; and like organic polymers.Another example thereof is polysiloxane type polymers such aspolydiorganosiloxane.

Preferred among those mentioned above are organic polymers (A) having,as the main chain skeleton, saturated hydrocarbon type polymers such aspolyisobutylene, hydrogenated polyisoprene and hydrogenatedpolybutadiene, polyoxyalkylene type polymers, (meth)acrylate esterpolymers and polysiloxane type polymers, in view of their relatively lowglass transition temperature and of good low-temperature resistance ofcured products obtained therefrom.

The glass transition temperature of the reactive silyl group-containingorganic polymer (A) is not particularly restricted but preferably is nothigher than 20° C., more preferably not higher than 0° C., mostpreferably not higher than −20° C. When the glass transition temperatureis higher than 20° C., the viscosity of the curable compositionincreases in the winter season or in cold districts, developing atendency toward lowered workability and, further, the flexibility ofcured products obtained decreases and the elongation thereof tends todecrease.

The glass transition temperature mentioned above can be determined byDSC measurement according to the method prescribed in JIS K 7121.

A curable composition including, as the main component, an organicpolymer whose main chain skeleton is a saturated hydrocarbon typepolymer, a polyoxyalkylene type polymer or a (meth)acrylate esterpolymer is more preferred since, when it is used as an adhesive orsealant, low-molecular-weight components scarcely migrate to (i.e.stain) adherends.

Further, an organic polymer whose main chain skeleton is apolyoxyalkylene type polymer or a (meth)acrylate ester polymer isparticularly preferred since it is high in moisture permeability and,when used as a main component of a one-pack type adhesive or sealant, itis excellent in depth curability and gives cured products excellent inadhesiveness. Most preferred is an organic polymer whose main chainskeleton is a polyoxyalkylene type polymer.

The polyoxyalkylene type polymer to be used as the main chain skeletonof the organic polymer (A) is a polymer having a repeating unitrepresented by the formula (3):

—R⁸—O—  (3)

(R⁸ is a straight or branched alkylene group containing 1 to 14 carbonatoms).

The group R⁸ in the formula (3) is not particularly restricted providedthat it is one of the straight or branched alkylene groups containing 1to 14 carbon atoms and, among those, straight or branched alkylenegroups containing 2 to 4 carbon atoms are preferred.

The repeating unit defined by the formula (3) is not particularlyrestricted but includes, for example, —CH₂O—, —CH₂CH₂O—, —CH₂CH (CH₃)O—,—CH₂CH (C₂H₅)O—, —CH₂C(CH₃)₂O— and —CH₂CH₂CH₂CH₂O—.

The polyoxyalkylene type polymer may have one repeating unit species ora plurality of repeating unit species. In the case of use in the fieldof sealants and the like, in particular, an organic polymer (A) in whichthe main component of the main chain skeleton is a propylene oxidepolymer is preferred since such polymer is noncrystalline and relativelylow in viscosity.

A method of producing such a polyoxyalkylene type polymer is notparticularly restricted but may be any of the methods known in the art.For example, mention may be made of the method using an alkali catalystsuch as KOH, the method disclosed in Japanese Kokai PublicationS61-215623 which uses, as a catalyst, a transition metal-porphyrincomplex, such as a complex obtained by reacting an organoaluminumcompound with porphyrin, the methods disclosed in Japanese KokokuPublications S46-27250 and S59-15336 and U.S. Pat. Nos. 3,278,457,3,278,458, 3,278,459, 3,427,256, 3,427,334 and 3,427,335, among others,which use, as a catalyst, a double metal cyanide complex, the methoddisclosed in Japanese Kokai Publication H10-273512 which uses, as acatalyst, a polyphosphazene salt, and the method disclosed in JapaneseKokai Publication H11-060722 which uses, as a catalyst, a phosphazenecompound.

A method of producing a reactive silyl group-containing polyoxyalkylenetype polymer is not particularly restricted but maybe any of the methodsknown in the art. For example, mention may be made of the methodsdisclosed in Japanese Kokoku Publications S45-36319 and S46-12154,Japanese Kokai Publications S50-156599, S54-6096, S55-13767, S55-13468and S57-164123, Japanese Kokoku Publication H03-2450 and U.S. Pat. Nos.3,632,557, 4,345,053, 4,366,307 and 4,960,844, among others, and themethods disclosed in Japanese Kokai Publications S61-197631, S61-215622,S61-215623, S61-218632, H03-72527, H03-47825 and H08-231707, amongothers, according to which polymers high in molecular weight (numberaverage molecular weight of 6,000 or higher) and narrow in molecularweight distribution (Mw/Mn of 1.6 or below) can be obtained.

In formulating the curable composition using the reactive silylgroup-containing polyoxyalkylene type polymer mentioned above, thepolymer may include a single species or a combination of a plurality ofspecies thereof.

The saturated hydrocarbon type polymer to be used as the main chainskeleton of the organic polymer (A) is a polymer whose molecules aresubstantially free of any carbon-carbon unsaturated bond, except for anaromatic ring, and is excellent in heat resistance, weather resistance,durability and a moisture barrier property.

The saturated hydrocarbon type polymer is not particularly restrictedbut there may be mentioned (1) polymers derived from an olefin typecompound containing 2 to 6 carbon atoms, such as ethylene, propylene,1-butene and isobutylene as the repeating unit species, (2) polymersderived from a diene type compound such as butadiene and isoprene as therepeating unit species, and (3) polymers obtained by copolymerizing theabove-mentioned diene type compound and the above-mentioned olefin typecompound, followed by hydrogenation and the like. Among these,isobutylene type polymers and hydrogenated polybutadiene type polymersare preferred in view of ease of functional-group introduction into anend thereof, ease of molecular weight control and adjustability of thenumber of terminal functional groups, among others; isobutylene typepolymers are more preferred.

The isobutylene type polymer may be such one that all of the repeatingunits are derived from isobutylene or a copolymer with another compound.When the isobutylene type copolymer is used as the main chain skeleton,the polymer preferably has an isobutylene-derived repeating unitcontent, in each molecule, of not lower than 50% by weight, morepreferably not lower than 80% by weight, particularly preferably 90 to99% by weight, so that the cured products obtained may have excellentrubber properties.

A method of producing the saturated hydrocarbon type polymer is notparticularly restricted but may be any of various conventionalpolymerization methods. Among them, the living polymerization method thedevelopment of which has been remarkable in recent years is preferredand, for example, the Inifer polymerization found by Kennedy et al. (J.P. Kennedy et al., J. Polymer Sci., Polymer Chem. Ed., 1997, 15, p.2843) may be mentioned as a method of producing isobutylene-basedpolymers using the living polymerization method. This polymerizationmethod enables introduction of various functional groups into molecularends and the isobutylene type polymers obtained are known to have amolecular weight of about 500 to 100,000 with a molecular weightdistribution of not broader than 1.5.

A method of producing a reactive silyl group-containing saturatedhydrocarbon type polymer is not particularly restricted but may be anyof the methods known in the art, for example the methods disclosed inJapanese Kokoku Publications H04-69659 and H07-108928, Japanese KokaiPublications S63-254149, S64-22904 and H01-197509 and Japanese PatentsNos. 2539445 and 2873395 and Japanese Kokai Publication H07-53882.

In formulating the curable composition using the above-mentionedreactive silyl group-containing saturated hydrocarbon type polymer, thepolymer may include a single species or a combination of a plurality ofspecies thereof.

A (meth)acrylate ester polymer to be used as the main chain skeleton ofthe organic polymer (A) is a polymer in which the repeating unit isderived from a (meth)acrylate ester compound. The expression“(meth)acrylate ester” refers to an acrylate ester and/or a methacrylateester and has the same meaning also in the description which follows.

The (meth)acrylate ester compound to be used as the repeating unit isnot particularly restricted but includes such (meth)acrylate compoundsas (meth)acrylic acid, methyl(meth)acrylate, ethyl(meth)acrylate,n-propyl(meth)acrylate, isopropyl(meth)acrylate, n-butyl(meth)acrylate,isobutyl(meth)acrylate, tert-butyl(meth)acrylate,n-pentyl(meth)acrylate, n-hexyl(meth)acrylate, cyclohexyl(meth)acrylate,n-heptyl(meth)acrylate, n-octyl(meth)acrylate,2-ethylhexyl(meth)acrylate, nonyl(meth)acrylate, decyl(meth)acrylate,dodecyl(meth)acrylate, phenyl(meth)acrylate, toluyl(meth)acrylate,benzyl(meth)acrylate, 2-methoxyethyl(meth)acrylate,3-methoxybutyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate,2-hydroxypropyl(meth)acrylate, stearyl(meth)acrylate,glycidyl(meth)acrylate, γ-(methacryloyloxypropyl)trimethoxysilane,γ-(methacryloyloxypropyl)dimethoxymethylsilane, (meth)acrylicacid-ethylene oxide adducts, trifluoromethylmethyl(meth)acrylate,2-trifluoromethylethyl(meth)acrylate,2-perfluoroethylethyl(meth)acrylate,2-perfluoroethyl-2-perfluorobutylethyl(meth)acrylate,perfluoroethyl(meth)acrylate, trifluoromethyl(meth)acrylate,bis(trifluoromethyl)methyl(meth)acrylate,2-trifluoromethyl-2-perfluoroethylethyl(meth)acrylate,2-perfluorohexylethyl(meth)acrylate, 2-perfluorodecylethyl(meth)acrylateand 2-perfluorohexadecylethyl(meth)acrylate.

The (meth)acrylate ester polymer includes copolymers of a (meth)acrylateester compound and a vinyl compound copolymerizable therewith. The vinylcompound is not particularly restricted but includes: styrene compoundssuch as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, andstyrenesulfonic acid and salts thereof; silyl group-containing vinylcompounds such as vinyltrimethoxysilane and vinyltriethoxysilane; maleicacid, maleic anhydride, and maleic acid monoalkyl esters and dialkylesters; fumaric acid and fumaric acid monoalkyl esters and dialkylesters; maleimide type compounds such as maleimide, methylmaleimide,ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide,octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide andcyclohexylmaleimide; nitrile group-containing vinyl compounds such asacrylonitrile and methacrylonitrile; amide group-containing vinylcompounds such as acrylamide and methacrylamide; vinyl esters such asvinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate andvinyl cinnamate; alkenes such as ethylene and propylene; conjugateddienes such as butadiene and isoprene; vinyl chloride, vinylidenechloride, allyl chloride and allyl alcohol. It is also possible to use aplurality of these as copolymerization components.

Among the (meth)acrylate ester polymers obtained from the compoundsmentioned above, those organic polymers which include, as the main chainskeleton, a copolymer of a styrene compound and a (meth)acrylatecompound are preferred since they give cured products excellent inphysical properties; those organic polymers which include, as the mainchain skeleton, a copolymer of an acrylate ester compound and amethacrylate ester compound are more preferred, and those organicpolymers which include, as the main chain skeleton, a polymer of anacrylate ester compound are particularly preferred.

For use in general architectural fields, the curable composition isrequired to be low in viscosity, while the cured products obtainedtherefrom are required to be low in modulus and high in elongation,weather resistance and thermal stability.

More preferred as ones meeting these requirements are organic polymers(A) whose main chain skeleton is derived from a butyl acrylate compound.

On the other hand, for use in automotive or like fields, the curedproducts obtained are required to be excellent in oil resistance.

More preferred as one giving cured products excellent in oil resistanceis an organic polymer (A) whose main chain skeleton is a copolymermainly derived from ethyl acrylate.

Curable compositions including the organic polymer (A) whose main chainskeleton is an ethyl acrylate-based copolymer tend to give curedproducts somewhat inferior in low-temperature properties(low-temperature resistance) in spite of their being excellent in oilresistance. For improving the low-temperature properties, replacement ismade of a part of ethyl acrylate with butyl acrylate. Since, however, anincreased proportion of butyl acrylate tends to impair the good oilresistance, the proportion thereof is preferably not higher than 40%,and more preferably not higher than 30%, in cases of a field where oilresistance is required.

The use, as a comonomer component, of 2-methoxyethyl acrylate,2-ethoxyethyl acrylate, or the like which has an oxygen atom introducedinto the side chain alkyl group is also preferred for improvinglow-temperature properties and the like without causing decrease in oilresistance.

Since, however, the introduction of an alkoxy group having an ether bondin the side chain tends to render the cured products obtained inferiorin thermal stability, the proportion thereof is preferably not higherthan 40% in cases of use where thermal stability is required.

As mentioned above, it is possible to obtain an organic polymer (A)whose main chain skeleton is an ethyl acrylate-based copolymer and whichis suited for various uses or can meet requirements by selecting thecomonomer component species and varying the proportion thereof takinginto consideration such physical properties as oil resistance, thermalstability and low temperature properties as required of the curedproducts obtained. For example, there may be mentioned, without anylimitative meaning, copolymers of ethyl acrylate, butyl acrylate and2-methoxyethyl acrylate (weight ratio: 40-50/20-30/30-20) as examplesexcellent in balance among such physical properties as oil resistance,thermal stability and low-temperature properties.

In the practice of the present invention, these preferred compounds maybe copolymerized and, further, block-copolymerized with another compoundand, on such occasion, the content of these preferred compounds ispreferably not lower than 40% by weight.

A method of producing the (meth)acrylate ester polymer is notparticularly restricted but may be any of the methods known in the art.Among them, the living radical polymerization method is preferably usedin particular in view of the ease of high-rate introduction of acrosslinking functional group into a molecular chain end and thecapability of obtaining polymers narrow in molecular weight distributionand low in viscosity.

The polymers obtained by ordinary free radical polymerization using, forexample, an azo compound or peroxide as a polymerization initiator tendto show an increased molecular weight distribution value generally notlower than 2 and an increased level of viscosity.

Among the methods of producing (meth)acrylate ester polymers using theabove-mentioned “living radical polymerization method”, the “atomtransfer radical polymerization method” which uses an organic halide orsulfonyl halide compound as an initiator and a transition metal complexas a catalyst is preferred as the method of producing (meth)acrylateester polymers containing a specific functional group since it has notonly such properties of the “living radical polymerization” as thecapability to give polymers narrow in molecular weight distribution andlow in viscosity but also a high degree of freedom in selecting theinitiator and catalyst and the capability to provide the polymers with ahalogen or the like at ends thereof relatively advantageous tofunctional-group exchange reactions. As for the atom transfer radicalpolymerization method, there may be mentioned, for example, the methoddescribed in Matyjaszewski et al., Journal of the American ChemicalSociety (J. Am. Chem. Soc.), 1995, 117, p. 5614.

A method of producing a reactive silyl group-containing (meth)acrylateester polymer is not particularly restricted but includes, for example,the free radical polymerization method using a chain transfer agent, asdisclosed in Japanese Kokoku Publications H03-14068 and H04-55444 andJapanese Kokai Publication H06-211922, the atom transfer radicalpolymerization method disclosed in Japanese Kokai PublicationH09-272714, and the like.

It is also possible to use a (meth)acrylate ester copolymer derived froma plurality of the (meth)acrylate ester compounds mentioned above as themain chain skeleton of the organic polymer (A).

As typical examples of the (meth)acrylate ester copolymer derived from aplurality of (meth)acrylate ester compounds, there may be mentionedcopolymers whose main chain skeleton substantially comprises: arepeating unit having an alkyl group containing 1 to 8 carbon atoms asrepresented by the formula (4):

—CH₂—C(R⁹))(COOR¹⁰)—  (4)

(R⁹ is a hydrogen atom or a methyl group and R¹⁰ is an alkyl groupcontaining 1 to 8 carbon atoms); and a repeating unit having an alkylgroup containing 9 or more carbon atoms as represented by the formula(5):

—CH₂—C(R⁹)(COOR¹¹)—  (5)

(R⁹ is as defined above referring to the formula (4) and R¹¹ is an alkylgroup containing 9 or more carbon atoms).

The group R¹⁰ in the formula (4) is not particularly restricted providedthat it is one of the alkyl groups containing 1 to 8 carbon atoms, forexample a methyl group, an ethyl group, a propyl group, an n-butylgroup, a t-butyl group and a 2-ethylhexyl group; among these, alkylgroups containing 1 to 4 carbon atoms are preferred. The group R¹⁰contained in the copolymers is not always restricted to a single alkylgroup species.

The group R¹¹ in the formula (5) is not particularly restricted providedthat it is one of the alkyl groups containing 9 or more carbon atoms,for example a lauryl group, a tridecyl group, a cetyl group, a stearylgroup and a behenyl group. Among these, alkyl groups containing 10 to 30carbon atoms are preferred and long-chain alkyl groups containing 10 to20 carbon atoms are more preferred. The group R¹¹ contained in thecopolymers is not always restricted to a single alkyl group species.

The (meth)acrylate ester copolymer substantially comprises the repeatingunits defined by the formula (4) and formula (5). The term“substantially” as used herein means that the total content of therepeating units defined by the formulas (4) and (5) in the copolymer isin excess of 50% by weight, and the total content of the repeating unitsdefined by the formulas (4) and (5) in the copolymer is preferably notlower than 70% by weight.

The content ratio between the repeating units of formulas (4) and (5)occurring in the copolymer as expressed in terms of the weight ratio(formula (4): formula (5)) is preferably 95:5 to 40:60, and morepreferably 90:10 to 60:40.

The (meth)acrylate ester copolymer includes a copolymer of(meth)acrylate ester compounds used as the repeating units defined bythe formulas (4) and (5) and a vinyl compound copolymerizable therewith.

As the vinyl compound, there may be mentioned, for example, acrylicacids such as acrylic acid and methacrylic acid; amide group-containingcompounds such as acrylamide, methacrylamide, N-methylolacrylamide andN-methylolmethacrylamide, epoxy group-containing compounds such asglycidyl acrylate and glycidyl methacrylate, amino group-containingcompounds such as diethylaminoethyl acrylate,diethylaminoethylmethacrylate and aminoethyl vinyl ether; and, further,such compounds as acrylonitrile, styrene, α-methylstyrene, alkyl vinylethers, vinyl chloride, vinyl acetate, vinyl propionate and ethylene.

In the main chain skeleton of the organic polymer (A), there may furtherbe present, if necessary, another repeating unit containing, forexample, a urethane bond, so long as the effects of the presentinvention are not significantly lessened thereby.

The urethane bond-containing repeating unit is not particularlyrestricted but there may be mentioned, for example, a repeating unitincluding a group formed by the reaction between an isocyanato group andan active hydrogen group (the group thus formed is hereinafter referredto also as an “amide segment”).

The amide segment is an organic group represented by the formula (6):

—NR¹²—C(═O)—  (6)

(R¹² is a hydrogen atom or an organic group).

The amide segment is not particularly restricted but includes, forexample, a urethane group formed by the reaction between an isocyanatogroup and a hydroxyl group; a urea group formed by the reaction betweenan isocyanato group and an amino group; and a thiourethane group formedby the reaction between an isocyanato group and a mercapto group.

Those organic groups formed by the reaction of an active hydrogen in theurethane group, the urea group and the thiourethane group with anisocyanato group also fall within the definition of “amide segment” asgiven herein.

A method of producing a reactive silyl group-containing organic polymercontaining the amide segment in the main chain skeleton thereof is notparticularly restricted but there may be mentioned, for example, themethod comprising reacting an active hydrogen-terminated organicgroup-containing organic polymer with an excess of a polyisocyanatecompound to give a polymer having an isocyanato group at a polyurethanetype main chain end and, thereafter or simultaneously therewith,reacting all or part of the isocyanato groups in the polymer with agroup W in a silicon compound represented by the formula (7):

W—R¹³—SiR¹⁴ _(3-a)X³ _(a)   (7)

(R¹³ is a divalent organic group, more preferably a divalent hydrocarbongroup containing 1 to 20 carbon atoms; the (3-a) R¹⁴s are hydrogen atomsor organic groups, the a X³ groups are hydroxyl groups or hydrolyzablegroups, and a is an integer of 1 to 3; and W is a group containing atleast one active hydrogen selected from the group consisting of ahydroxyl group, a carboxyl group, a mercapto group and an amino (primaryor secondary) group), as disclosed in Japanese Kokoku PublicationS46-12154 (U.S. Pat. No. 3,632,557), Japanese Kokai PublicationsS58-109529 (U.S. Pat. No. 4,374,237), S62-13430 (U.S. Pat. No.4,645,816), H08-53528 (EP 0676403), and H10-204144 (EP 0831108),Japanese Kohyo Publication 2003-508561 (U.S. Pat. No. 6,197,912),Japanese Kokai Publications H06-211879 (U.S. Pat. No. 5,364,955),H10-53637 (U.S. Pat. No. 5,756,751), H11-100427, 2000-169544,2000-169545 and 2002-212415, Japanese Patent 3,313,360, U.S. Pat. Nos.4,067,844 and 3,711,445, Japanese Kokai Publication 2001-323040, and thelike.

Mention may also be made of the method comprising reacting an activehydrogen-containing group occurring at an end of an organic polymer withthe isocyanato group of a reactive silyl group-containing isocyanatecompound represented by the formula (8):

O═C═N—R¹³—SiR¹⁴ _(3-a)X³ _(a)   (8)

(R¹³, R¹⁴, X³ and a are as defined above referring to the formula (7)),as disclosed in Japanese Kokai Publications H11-279249 (U.S. Pat. No.5,990,257), 2000-119365 (U.S. Pat. No. 6,046,270), S58-29818 (U.S. Pat.No. 4,345,053), H03-47825 (U.S. Pat. No. 5,068,304), H11-60724,2002-155145 and 2002-249538, WO 03/018658, WO 03/059981, and the like.

The active hydrogen-terminated group-containing organic polymer is notparticularly restricted but includes, for example, hydroxylgroup-terminated oxyalkylene polymers (polyether polyols), polyacrylicpolyols, polyester polyols, hydroxyl group-terminated saturatedhydrocarbon type polymers (polyolefin polyols), polythiol compounds andpolyamine compounds.

Preferred among these are those organic polymers whose main chainskeleton includes a polyether polyol, polyacrylic polyol or polyolefinpolyol component, since they have a relatively low glass transitiontemperature and give cured products excellent in low-temperatureresistance.

Those organic polymers including a polyether polyol component are low inviscosity, have good workability and give cured products showing gooddepth curability and adhesiveness, hence are particularly preferred.Curable compositions which include an organic polymer containing apolyacrylic polyol or saturated hydrocarbon type polymer component aremore preferred since they give cured products having good weatherresistance and thermal stability.

The polyether polyol preferably has, on an average, at least 0.7terminal hydroxyl group per molecule.

The production method thereof is not particularly restricted but may beany of the methods known in the art, including, for example, apolymerization method using an alkali metal catalyst, and apolymerization method of an alkylene oxide using a polyhydroxy compoundcontaining at least two hydroxyl groups per molecule as an initiator inthe presence of a double metal cyanide complex or cesium.

Among the polymerization methods mentioned above, the polymerizationmethod using a double metal cyanide complex is preferred since it givespolymers low in degree of unsaturation, narrow in molecular weightdistribution (Mw/Mn) and low in viscosity, which give cured productsexcellent in acid resistance and weather resistance, among others.

The term “polyacrylic polyol” refers to a polyol whose skeleton is a(meth)acrylic acid alkyl ester (co)polymer and whose molecule contains ahydroxyl group.

As for the production method thereof, the living radical polymerizationmethod is preferred and the atom transfer radical polymerization methodis more preferred because of capability of their giving polymers narrowin molecular weight distribution and possibly low in viscosity. Alsopreferred is the polymerization method involving the so-called SGOprocess in which an acrylic acid alkyl ester type compound iscontinuously bulk-polymerized under high-temperature and high-pressureconditions, as disclosed in Japanese Kokai Publication 2001-207157. Assuch a polyacrylic polyol, there may be mentioned ARUFON UH-2000(product of Toagosei Co., Ltd.), and the like.

The polyisocyanate compound is not particularly restricted but includes,for example, an aromatic type polyisocyanate such astoluene(tolylene)diisocyanate, diphenylmethane diisocyanate and xylylenediisocyanate; and an aliphatic type polyisocyanate such as isophoronediisocyanate and hexamethylene diisocyanate.

The silicon compound defined by the formula (7) is not particularlyrestricted but there may be mentioned, for example, aminogroup-containing silane compounds such as γ-aminopropyltrimethoxysilane,N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane,γ-(N-phenyl)aminopropyltrimethoxysilane,N-ethylaminoisobutyltrimethoxysilane,N-cyclohexylaminomethyltriethoxysilane,N-cyclohexylaminomethyldiethoxymethylsilane andN-phenylaminomethyltrimethoxysilane; hydroxyl group-containing silanecompounds such as γ-hydroxypropyltrimethoxysilane; and mercaptogroup-containing silane compounds such asγ-mercaptopropyltrimethoxysilane.

As the silicon compound represented by the formula (7), there mayfurther be mentioned Michael addition products derived from variousα,β-unsaturated carbonyl compounds and a primary amino group-containingsilane compound or Michael addition products derived from various(meth)acryloyl group-containing silane compounds and a primary aminogroup-containing compound, as disclosed in Japanese Kokai PublicationsH06-211879 (U.S. Pat. No. 5,364,955), H10-53637 (U.S. Pat. No.5,756,751), H10-204144 (EP 0831108), 2000-169544 and 2000-169545.

The reactive silyl group-containing isocyanate compound defined by theformula (8) is not particularly restricted but includes, for example,γ-trimethoxysilylpropyl isocyanate, γ-triethoxysilylpropyl isocyanate,γ-methyldimethoxysilylpropyl isocyanate, γ-methyldiethoxysilylpropylisocyanate, trimethoxysilylmethyl isocyanate, triethoxysilylmethylisocyanate, dimethoxymethylsilylmethyl isocyanate anddiethoxymethylsilylmethyl isocyanate.

As the reactive silyl group-containing isocyanate compound defined bythe formula (8), there may further be mentioned the reaction productsderived from a silicon compound of the formula (7) and an excess of apolyisocyanate compound, as disclosed in Japanese Kokai Publication2000-119365 (U.S. Pat. No. 6,046,270).

The hydrolyzable group represented by X¹ in the formula (2) is notparticularly restricted but includes those hydrolyzable groups which areknown in the art, for example, a hydrogen atom, halogen atoms, and analkoxy group, an acyloxy group, a ketoxymate group, an amino group, anamide group, an acid amide group, an aminooxy group, a mercapto groupand an alkenyloxy group. Among these, a hydrogen atom, an alkoxy group,an acyloxy group, a ketoxymate group, an amino group, an amide group, anaminooxy group, a mercapto group and an alkenyloxy group are preferred,and an alkoxy group is more preferred from the viewpoints of mildhydrolyzability and easy handleability.

One silicon atom can have one to three groups selected from ahydrolyzable group or a hydroxyl group bound thereto. When the siliconatom in the reactive silyl group has two or more hydrolyzable groups andhydroxyl groups bound thereto, these groups may be the same group or maybe different groups.

The group R¹ in the formula (2) is not particularly restricted butincludes, for example, an alkyl group such as a methyl group and anethyl group, a cycloalkyl group such as a cyclohexyl group, an arylgroup such as a phenyl group, and an aralkyl group such as a benzylgroup. Among these, a methyl group is preferred.

The reactive silyl group defined by the formula (2) is not particularlyrestricted but includes, for example, a trimethoxysilyl group, atriethoxysilyl group, a triisopropoxysilyl group, a dimethoxymethylsilylgroup, a diethoxymethylsilyl group, a diisopropoxymethylsilyl group, amethoxydimethylsilyl group and an ethoxydimethylsilyl group. Amongthese, a trimethoxysilyl group, a triethoxysilyl group and adimethoxymethylsilyl group are preferred since they have high activityand afford good curability, and a trimethoxysilyl group is morepreferred.

Further, a dimethoxymethylsilyl group is particularly preferred becauseof good curability and storage stability of the curable compositionobtained. A triethoxysilyl group is particularly preferred since thealcohol formed upon hydrolysis reaction of the reactive silyl group ishighly safe ethanol.

A method of introducing the reactive silyl group is not particularlyrestricted but includes such methods known in the art as the methods (a)to (c) shown below.

(a) A method comprising: reacting a polymer containing such a functionalgroup as a hydroxyl group in the molecule with an organic compoundcontaining an active group reactive with this functional group as wellas an unsaturated group to give an unsaturated group-containing polymer;or copolymerizing a polymer containing such a functional group as ahydroxyl group in the molecule with an unsaturated group-containingepoxy compound to give an unsaturated group-containing polymer, and thenreacting the reaction product obtained with a reactive silylgroup-containing hydrosilane for hydrosilylation.

(b) A method comprising reacting the unsaturated group-containingorganic polymer obtained in the same manner as described above in (a)with a compound containing a mercapto group and a reactive silyl group.

(c) A method comprising reacting an organic polymer containing such afunctional group as a hydroxyl group, an epoxy group or an isocyanatogroup in the molecule with a compound containing a functional groupreactive with said function group and a reactive silyl group.

Among these methods, the method (a) or the method (c) in such a modethat a hydroxyl group-terminated polymer is reacted with a compoundcontaining an isocyanato group and reactive silyl group is preferred inview of the fact that a high conversion rate can be attained in arelatively short period of time. The method (a) is more preferred sincecurable compositions based on the reactive silyl group-containingorganic polymer obtained by the method (a) tend to be lower in viscositythan curable compositions based on the organic polymer obtained by themethod (c) and, as a result, curable compositions having goodworkability can be obtained and, further, the organic polymer obtainedby the method (b) has a stronger mercaptosilane-derived odor as comparedwith the organic polymer obtained by the method (a).

The hydrosilane compound to be used in carrying out the method (a) isnot particularly restricted but includes, for example, halogenatedhydrosilanes such as trichlorosilane, methyldichlorosilane,dimethylchlorosilane and phenyldichlorosilane; alkoxysilanes such astrimethoxysilane, triethoxysilane, methyldiethoxysilane,methyldimethoxysilane, phenyldimethoxysilane and1-[2-(trimethoxysilyl)ethyl]-1,1,3,3-tetramethyldisiloxane;acyloxyhydrosilanes such as methyldiacetoxysilane andphenyldiacetoxysilane; and ketoxymatehydrosilanes such asbis(dimethylketoxymate)methylsilane andbis(cyclohexylketoxymate)methylsilane. Among these, halogenatedhydrosilanes and alkoxyhydrosilanes are preferred, andalkoxyhydrosilanes are more preferred because of the mildhydrolyzability and easy handleability of curable compositions based onthe organic polymer (A) obtained. Among the alkoxyhydrosilanes,methyldimethoxysilane is preferred because of its ready availability andexcellent various properties (curability, storage stability, elongationproperty, tensile strength, etc.) of curable compositions based on theorganic polymer (A) obtained and cured products obtained therefrom.

The synthetic method (b) is not particularly restricted but may be, forexample, the method of introducing a mercapto group- and reactive silylgroup-containing compound into an unsaturated-bond site in the organicpolymer by a radical addition reaction in the presence of a radicalinitiator and/or a radical generation source. The mercapto group- andreactive silyl group-containing compound is not particularly restrictedbut includes, for example, γ-mercaptopropyltrimethoxysilane,γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltriethoxysilane,γ-mercaptopropylmethyldiethoxysilane, mercaptomethyltrimethoxysilane andmercaptomethyltriethoxysilane.

The method of reacting a hydroxyl group-terminated polymer with anisocyanato group- and reactive silyl group-containing compound accordingto the synthetic method (c) is not particularly restricted but may be,for example, a method disclosed in Japanese Kokai Publication H03-47825.The isocyanato group- and reactive silyl group-containing compound isnot particularly restricted but includes, for example,γ-isocyanatopropyltrimethoxysilane,γ-isocyanatopropylmethyldimethoxysilane,γ-isocyanatopropyltriethoxysilane,γ-isocyanatopropylmethyldiethoxysilane,isocyanatomethyltrimethoxysilane, isocyanatomethyltriethoxysilane,isocyanatomethyldimethoxymethylsilane andisocyanatomethyldiethoxymethylsilane.

In the case of silane compounds containing a silicon atom with threehydrolyzable groups bound thereto, for example trimethoxysilane, thedisproportionation reaction may proceed rapidly in certain cases. Theprogress of the disproportionation reaction may sometimes result in theformation of such a dangerous compound as dimethoxysilane.

In the case of γ-mercaptopropyltrimethoxysilane andγ-isocyanatopropyltrimethoxysilane, however, such disproportionationreaction will not proceed. Therefore, in the case of using, as the silylgroup, a group containing a silicon atom with three hydrolyzable groupsbound thereto, for example a trimethoxysilyl group, the synthetic method(b) or (c) is preferably employed.

On the other hand, in the case of silane compounds represented by theformula (9):

H—(SiR⁶ ₂O)_(m)SiR⁶ ₂—R⁷—SiX² ₃   (9)

(wherein the three X²s each independently represent a hydroxyl group ora hydrolyzable group; the (2m+2) R⁶s each independently represent ahydrocarbon group, preferably, from the availability and cost viewpoint,a hydrocarbon group containing 1 to 20 carbon atoms, more preferably ahydrocarbon group containing 1 to 8 carbon atoms, particularlypreferably a hydrocarbon group containing 1 to 4 carbon atoms; R⁷ is adivalent organic group, preferably, from the availability and costviewpoint, a divalent C₁₋₁₂ hydrocarbon group, more preferably adivalent C₂₋₈ hydrocarbon group, particularly preferably a divalent C₂hydrocarbon group; and m is an integer of 0 to 19, preferably, from theavailability and cost viewpoint, 1), the disproportionation reactionwill not proceed. Therefore, for introducing a group containing asilicon atom with three hydrolyzable groups bound thereto by thesynthetic method (a), a silane compound represented by the formula (9)is preferably used.

As the silane compound represented by the formula (9), there may bementioned 1-[2-(trimethoxysilyl)ethyl]-1,1,3,3-tetramethyldisiloxane,1-[2-(trimethoxysilyl)propyl]-1,1,3,3-tetramethyldisiloxane and1-[2-(trimethoxysilyl)hexyl]-1,1,3,3-tetramethyldisiloxane.

The reactive silyl group-containing organic polymer (A) to be used mayhave either a straight chain structure or a branched chain structure inthe molecule thereof, and the number average molecular weight thereof,as expressed in terms of the value on a polystyrene equivalent basis asderived from the value measured by GPC, is preferably 500 to 100,000,more preferably 1,000 to 50,000, particularly preferably 3,000 to30,000. When the number average molecular weight is lower than 500, thecured products obtained tend to be inferior in elongation propertiesand, when it is in excess of 100,000, the resulting curable compositionbecomes high in viscosity and tends to be inferior in workability.

The number of reactive silyl groups contained in each molecule of theorganic polymer (A) is preferably not smaller than 1 on an average; itis preferably 1.1 to 5. When the number of reactive silyl groupscontained in each molecule is smaller than 1 on an average, the curablecomposition tends to be inferior in curability and the cured productsobtained show a tendency toward failure to exhibit a good rubber elasticbehavior.

The reactive silyl group may occur at a main chain end or at a sidechain end, or at both. In particular, when the reactive silyl groupoccurs only at a main chain end, the effective network size in theorganic polymer component contained in the cured products obtainedbecomes increased, so that it becomes easy to obtain rubber-like curedproducts showing high strength, high elongation and low elastic modulus.

The curable composition of the present invention includes, as anessential constituent, an amidine compound (B) represented by theformula (1):

R²N═CR³—NR⁴ ₂   (1)

(wherein R², R³, and the two R⁴s each independently represent a hydrogenatom or an organic group),which serves as a curing catalyst of the reactive silyl group-containingpolymer (A).

Use of the amidine compound (B) as a curing catalyst allows the curablecomposition of the present invention to have practical curability inspite of being a non-organotin type catalyst, and the obtained curedproducts to have good adhesiveness to various substrates.

As R² in the formula (1), a hydrogen atom or a hydrocarbon group ispreferred since they increase curability of the organic polymer (A), andmore preferred is a hydrocarbon group in which the carbon atom locatedin the a position with respect to the nitrogen atom does not have anunsaturated bond. In cases where R² is an organic group or a hydrocarbongroup, the number of carbon atoms contained therein is preferably 1 to20, and more preferably 1 to 10, from the ready-availability viewpoint.

As R³ in the formula (1), preferred is a hydrogen atom or an organicgroup represented by —NR⁵ ₂ (wherein the two R⁵s each independentlyrepresent a hydrogen atom or an organic group) since they can enhancecurability of the organic polymer (A), and an organic group representedby —NR⁵ ₂ is more preferred.

It is to be noted that the amidine compound defined by the formula (1)wherein R³ is an organic group represented by the above-mentioned —NR⁵ ₂is referred to as a guanidine compound. The guanidine compound ispreferably a compound in which R⁵ is a hydrogen atom or a C₁₋₂₀hydrocarbon group, and preferably a compound in which R⁵ is a hydrogenatom or a C₁₋₁₀ hydrocarbon group, because of its ready availability anda great effect of increasing curability of the organic polymer (A).

Because of good adhesiveness of the cured products obtained, R³ in theformula (1) is preferably an organic group represented by—NR¹⁵—C(═NR¹⁶)—NR¹⁷ ₂ (wherein R¹⁵, R¹⁶ and the two R¹⁷s eachindependently represent a hydrogen atom or an organic group) and/or—N═C(═NR¹⁸ ₂)—NR¹⁹ ₂ (wherein the two R¹⁸s and two R¹⁹s eachindependently represent a hydrogen atom or an organic group).

It is to be noted that the amidine compound defined by the formula (1)wherein R³ is such an organic group as the —NR¹⁵—C(═NR¹⁶)—NR¹⁷ ₂ or—N═C(═NR¹⁸ ₂)—NR¹⁹ ₂ mentioned above is referred to as a biguanidecompound.

The biguanide compound defined by the formula (1) wherein R³ is anorganic group represented by the —NR¹⁵—C(═NR¹⁶)—NR¹⁷ ₂ is preferably acompound in which R¹⁵, R¹⁶ and the two R¹⁷s each independently representa hydrogen atom or a C₁₋₂₀ hydrocarbon group, and more preferably acompound in which ^(R) ¹⁵, R¹⁶ and the two R¹⁷'s each independentlyrepresent a hydrogen atom or a C₁₋₁₀ hydrocarbon group, because of itsready availability and good adhesiveness of the cured products obtained.Furthermore, particularly preferred is a compound in which at least oneamong the R², two R⁴s, R¹⁵, R¹⁶, and two R¹⁷'s represent (s) an arylgroup since the adhesiveness of the cured products obtained can be moreimproved.

The biguanide compound in which R³ is an organic group represented bythe —N═C(═NR¹⁸ ₂)—NR¹⁹ ₂ is preferably a compound in which R², the twoR⁴s, R¹⁸ and the two R¹⁹s each independently represent a hydrogen atomor a C₁₋₂₀ hydrocarbon group, and more preferably a compound in whichR², the two R⁴s, R¹⁸ and the two R¹⁹s each independently represent ahydrogen atom or a C₁₋₁₀ hydrocarbon group, because of its readyavailability and good adhesiveness of the cured products obtained.

The two R⁴s in the formula (1) each represent preferably a hydrogen atomor a C₁₋₂₀ hydrocarbon group, and more preferably a hydrogen atom or aC₁₋₁₀ hydrocarbon group, because of its ready availability and theeffect of increasing curability of the organic polymer (A).

The number of carbon atoms contained in the amidine compound (B) of theformula (1) is preferably not smaller than 2, more preferably notsmaller than 6, and particularly preferably not smaller than 7.

When the number of carbon atoms is as small as less than 2 (namely, themolecular weight is low), the volatility of the compound becomesincreased, causing a tendency toward pollution of the work environment.It is not necessary to particularly specify the upper limit to thenumber of carbon atoms contained in the amidine compound (B); it isgenerally preferred, however, that the number of carbon atoms be nothigher than 10,000. For the same reasons as mentioned above, the amidinecompound (B) preferably has a molecular weight of not smaller than 60,more preferably not smaller than 120, and particularly preferably notsmaller than 130. It is not necessary to particularly specify the upperlimit to the molecular weight; it is generally preferred, however, thatthe molecular weight be not higher than 100,000.

The amidine compound (B) (inclusive of the guanidine compound andbiguanide compound) is not particularly restricted but includespyrimidine compounds such as pyrimidine, 2-aminopyrimidine,6-amino-2,4-dimethylpyrimidine, 2-amino-4,6-dimethylpyrimidine,1,4,5,6-tetrahydropyrimidine, 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine,1-ethyl-2-methyl-1,4,5,6-tetrahydropyrimidine,1,2-diethyl-1,4,5,6-tetrahydropyrimidine,1-n-propyl-2-methyl-1,4,5,6-tetrahydropyrimidine,2-hydroxy-4,6-dimethylpyrimidine, 1,3-diazanaphthalene, and2-hydroxy-4-aminopyrimidine; imidazoline compounds such as2-imidazoline, 2-methyl-2-imidazoline, 2-ethyl-2-imidazoline,2-propyl-2-imidazoline, 2-vinyl-2-imidazoline,1-(2-hydroxyethyl)-2-methyl-2-imidazoline,1,3-dimethyl-2-iminoimidazolidine and1-methyl-2-iminoimidazolidine-4-one; amidine compounds such as1,8-diazabicyclo[5.4.0]undec-7-ene (hereinafter referred to as DBU),1,5-diazabicyclo[4.3.0]non-5-ene,2,9-diazabicyclo[4.3.0]non-1,3,5,7-tetraene,6-(dibutylamino)-1,8-diazabicyclo[5.4.0]undecene-7 (hereinafter referredto as DBA-DBU); guanidine compounds such as guanidine, dicyandiamide,1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine,1-phenylguanidine, 1-(o-tolyl)guanidine, 1,1-dimethylguanidine,1,3-dimethylguanidine, 1,2-diphenylguanidine, 1,1,2-trimethylguanidine,1,2,3-trimethylguanidine, 1,1,3,3-tetramethylguanidine,1,1,2,3,3-pentamethylguanidine, 2-ethyl-1,1,3,3-tetramethylguanidine,1,1,3,3-tetramethyl-2-n-propylguanidine,1,1,3,3-tetramethyl-2-isopropylguanidine,2-n-butyl-1,1,3,3-tetramethylguanidine,2-tert-butyl-1,1,3,3-tetramethylguanidine, 1,2,3-tricyclohexylguanidine,1-benzyl-2,3-dimethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene,7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene,7-ethyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene,7-n-propyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene,7-isopropyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene,7-n-butyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene,7-cyclohexyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, and7-n-octyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene; and biguanide compoundssuch as biguanide, 1-methylbiguanide, 1-ethylbiguanide,1-n-butylbiguanide, 1-(2-ethylhexyl)biguanide, 1-n-octadecylbiguanide,1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide,1-allylbiguanide, 1-phenylbiguanide, 1-(o-tolyl)biguanide,1-morpholinobiguanide, 1-n-butyl-N²-ethylbiguanide,1,1′-ethylenebisbiguanide, 1,5-ethylenebiguanide,1-[3-(diethylamino)propyl]biguanide,1-[3-(dibutylamino)propyl]biguanide, andN′,N″-dihexyl-3,12-diimino-2,4,11,13-tetraazatetradecanediamidine.

Either a single species among these amidine compounds may beincorporated in the curable composition or a combination of a pluralitythereof may be incorporated in the curable composition.

Preferred among those amidine compounds mentioned above are1-(o-tolyl)biguanide, 1-phenylbiguanide, 1-(o-tolyl)guanidine,1-phenylguanidine, 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine,1,5,7-triazabicyclo[4.4.0]dec-5-ene,7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, and like guanidinecompounds, since they are highly active and can impart good curabilityto the organic polymer (A).

Further, 1-(o-tolyl)biguanide, 1-phenylbiguanide, 1-(o-tolyl)guanidine,and 1-phenylguanidine are more preferred since they are readilyavailable and can enhance curability of the organic polymer (A) and thecured products obtained show good adhesiveness.

The addition level of the amidine compound (B) is preferably 0.1 to 30parts by weight, and more preferably 0.1 to 12 parts by weight, per 100parts by weight of the organic polymer (A). When the addition level ofthe amidine compound (B) is below 0.1 parts by weight, the curablecomposition may fail to obtain a practical rate of curing and it tendsto become difficult for the curing reaction to proceed to a sufficientextent. On the other hand, when the level of addition of the amidinecompound (B) is above 30 parts by weight, the curing time of the curablecomposition becomes too short, hence the workability tends to becomeworsened.

While the curable composition of the present invention uses an amidinecompound as a curing catalyst, another curing catalyst can be used incombination, if necessary, so long as the effects of the presentinvention will not be reduced.

The curing catalyst other than the amidine compound is not particularlyrestricted but includes, for example, carboxylic acid metal salts suchas tin carboxylates, lead carboxylates, bismuth carboxylates, potassiumcarboxylates, calcium carboxylates, barium carboxylates, titaniumcarboxylates, zirconium carboxylates, hafnium carboxylates, vanadiumcarboxylates, manganese carboxylates, iron carboxylates, cobaltcarboxylates, nickel carboxylates and cerium carboxylates; titaniumcompounds such as tetrabutyl titanate, tetrapropyl titanate, titaniumtetrakis(acetylacetonate), bis(acetylacetonato)diisopropoxytitanium anddiisopropoxytitanium bis(ethyl acetoacetate); organotin compounds suchas dibutyltin dilaurate, dibutyltin maleate, dibutyltin phthalate,dibutyltin dioctanoate, dibutyltin bis(2-ethylhexanoate), dibutyltinbis(methyl maleate), dibutyltin bis(ethyl maleate), dibutyltin bis(butylmaleate), dibutyltin bis(octyl maleate), dibutyltin bis(tridecylmaleate), dibutyltin bis(benzyl maleate), dibutyltin diacetate,dioctyltin bis(ethyl maleate), dioctyltin bis(octyl maleate), dibutyltindimethoxide, dibutyltin bis(nonylphenoxide), dibutenyltin oxide,dibutyltin oxide, dibutyltin bis(acetylacetonate), dibutyltin bis(ethylacetoacetonate), reaction products of dibutyltin oxide-silicate compoundand reaction products of dibutyltin oxide-phthalic acid ester; aluminumcompounds such as aluminum tris(acetylacetonate), aluminum tris(ethylacetoacetate) and diisopropoxyaluminum ethyl acetoacetate; zirconiumcompounds such as zirconium tetrakis(acetylacetonate); various metalalkoxides such as tetrabutoxyhafnium; organic acidic phosphoric acidesters; organosulfonic acids such as trifluoromethanesulfonic acid;inorganic acids such as hydrochloric acid, phosphoric acid and boronicacid; and so forth.

The combined use of the curing catalysts other than the amidinecompounds with the amidine compounds is expected to increase thecatalytic activity and improve such properties as depth curability andthin layer curability of the curable composition, and adhesiveness ofthe cured products obtained.

Since, however, when an organotin compound is used in combination, thetoxicity of the curable composition tends to increase with the increasein organotin blending level, the blending level of the organotincompound is preferably small and, more specifically, it is preferablynot higher than 1 part by weight, more preferably not higher than 0.5parts by weight, and particularly preferably not higher than 0.05 partsby weight, per 100 parts by weight of the organic polymer (A);substantial absence thereof is most preferred.

In cases where a metal compound other than an organotin is used incombination, from the viewpoint of reduction in environmental stress,the blending level thereof is preferably small, more specifically ispreferably not higher than 5 parts by weight, and more preferably nothigher than 2 parts by weight, per 100 parts by weight of the organicpolymer (A), and substantial absence thereof is most preferred.

The curable composition of the present invention includes, as anessential constituent, a compound (C) containing a sulfonyl grouprepresented by —S(═O)₂— in a molecule thereof.

The sulfonyl group-containing compound (C) to be blended has a highsolubility to amidine compounds, and has a function to uniformlydisperse the amidine compound (B) into the curable composition. Blendingof the sulfonyl group-containing compound (C) into the curablecomposition makes it possible to adjust the viscosity and slump(sagging) properties of the curable composition, and mechanicalproperties (tensile strength, elongation, and the like) of the curedproducts obtained.

Since the sulfonyl group-containing compound (C) of the presentinvention is well compatible with the organic polymer (A), it does notisolate in the curable composition. The obtained cured products do notbleed out from the surface for a long period of time, and can maintainfavorable physical properties.

The sulfonyl group-containing compound (C) is not particularlyrestricted but includes, for example, benzenesulfonamide,N-methylbenzenesulfonamide, N-ethylbenzenesulfonamide,N-propylbenzenesulfonamide, N-n-butylbenzenesulfonamide,N-t-butylbenzenesulfonamide, N-pentylbenzenesulfonamide,N-hexylbenzenesulfonamide, N-heptylbenzenesulfonamide,N-octylbenzenesulfonamide, N-decylbenzenesulfonamide,N-dodecylbenzenesulfonamide, N-phenylbenzenesulfonamide,aminobenzenesulfonamide, p-ethylbenzenesulfonamide,p-propylbenzenesulfonamide, p-butylbenzenesulfonamide,2-aminophenolsulfonamide, p-chlorobenzenesulfonamide,p-acetaminobenzenesulfonamide, p-acetaminomethylbenzenesulfonamide,1-chlorobenzene-2,4-disulfonamide, phenylhydrazinesulfonamide,N,N′-bis(phenylsulfonyl)diphenyletherbissulfonamide,N,N′-bis(phenylsulfonyl)diphenylbissulfonamide,5-amino-2-methyl-N-(hydroxyethyl)-1-benzenesulfonamide, 2-aminobenzoicacid-5-sulfonamide, 2-aminobenzoic acid-5-N-methylsulfonamide,4-(2-aminoethyl)benzenesulfonamide,4-(2-ethylhexyloxy)benzenesulfonamide, 2-toluenesulfonamide,4-toluenesulfonamide, 4-aminobenzenesulfonamide,N-cyclohexyl-p-toluenesulfonamide, N-methyltoluenesulfonamide,N-ethyltoluenesulfonamide, N-propyltoluenesulfonamide,N-n-butyltoluenesulfonamide, N-t-butyltoluenesulfonamide,N-pentyltoluenesulfonamide, N-hexyltoluenesulfonamide,N-heptyltoluenesulfonamide, N-octyltoluenesulfonamide,N-decyltoluenesulfonamide, N-dodecyltoluenesulfonamide,N-phenyltoluenesulfonamide, 2-toluenesulfonamide, dimethylsulfone,dimethylsulfoxide, bis(2-hydroxyethyl)sulfone,bis(vinylsulfonylmethyl)ether, 4,4′-dichlorodiphenylsulfone,2-amino-4-methylsulfonylphenol, aminophenyl-β-hydroxyethylsulfone,diphenylsulfone, bis(4-methylphenyl)sulfone, 4,4′-dichlorodiphenylsulfone, bis(3-aminophenyl)sulfone, 2-aminodiphenylsulfone,bis(4-hydroxyphenyl)sulfone, bis{4-(3′-aminophenoxy)phenyl}sulfone,α,α,α-tribromomethylphenylsulfone, methyl-p-tolyl sulfone,(vinylsulfonyl)benzene, tetramethylene sulfone, 2-(methylsulfonyl)ethylchloroformate, thiamphenicol, 2-(methylsulfonyl)ethyl alcohol,2-aminophenol-4-ethylsulfone, 4,4′-oxybis(benzenesulfonylhydrazide),2-amino-1-(4-methylsulfonylphenyl)-1,3-propanediol, benzenesulfonicacid, 4-aminobenzenesulfonic acid, tetrahydrothiophene-1,1-dioxide, andthe like. These sulfonyl group-containing compounds may be used singlyor a plurality thereof may be used in combination.

In order to dissolve the amidine compound (B), the sulfonylgroup-containing compound (C) is preferably liquid at room temperature,and specifically, has a melting point of 50° C. or lower, and morepreferably of 30° C. or lower. The sulfonyl group-containing compound(C) preferably has a boiling point of 200° C. or higher at 760 mmHg soas to be less volatile. When the boiling point is lower than 200° C.,the sulfonyl group-containing compound (C) volatilizes upon use of thecurable composition including it in a room or the like, may cause atendency toward pollution of the work environment, and may have adverseeffect on human body.

A compound which has both an aryl group and a sulfonamide structure inone molecule thereof, such as benzenesulfonamide and toluenesulfonamide,is preferable in that it acts more effectively upon increasing thesolubility of the amidine compound (B). When this compound is used evenwith the amidine compound (B) having a low compatibility with theorganic compound (A), it is possible to prevent the amidine compound (B)from exuding from the curable composition.

Further, the compound having a structure in which a hydrogen atom of asulfonamide group is substituted with an alkyl group has a low meltingpoint and a high boiling point, hence it is preferable. The compoundshaving such a structure include N-ethyltoluenesulfonamide having aboiling point of 340° C. at 760 mmHg, N-n-butylbenzene sulfonamidehaving a boiling point of 314° C. at 760 mmHg, and the like. These arepreferable because they are less volatile and therefore less likely tobecome a VOC generation source.

These compounds are industrially and readily available from Fuji AmideChemical Co., Ltd., Toray Fine Chemicals Co., Ltd., PROVIRON Co., Ltd.in Belgium, and the like.

Tetrahydrothiophene-1,1-dioxide is preferable in that it easilydissolves the amidine compound (B), in particular, and its boiling pointat 760 mmHg is as high as 285° C. It is to be noted that anhydroustetrahydrothiophene-1,1-dioxide is preferable because good storagestability can be exhibited when it is added to a one-pack type curablecomposition.

Tetrahydrothiophene-1,1-dioxide is also referred to as tetramethylenesulfone, or sulfolane, and industrially and readily available fromSumitomo Seika Chemicals Co., Ltd., New Japan Chemical Co., Ltd., ShellSekiyu K.K., and the like.

The blending level of the sulfonyl group-containing compound (C) ispreferably 0.1 to 100 parts by weight, and more preferably 1 to 50 partsby weight, per 100 parts by weight of the organic polymer (A). When theblending level of the sulfonyl group-containing compound (C) is lessthan 0.1 parts by weight, the solubility of the amidine compound (B) maybe low. On the other hand, when the blending level of the sulfonylgroup-containing compound (C) is in excess of 100 parts by weight, thesagging resistance of the curable composition may be reduced to causepoor workability thereof.

The silane coupling agent (D) is desirably blended into the curablecomposition of the present invention. The silane coupling agent as usedherein refers to a compound having a hydrolyzable silyl group andfunctional groups other than the hydrolyzable silyl group in a molecule.Blending the silane coupling agent into the curable composition has theeffect of improving the adhesiveness of the obtained cured products tovarious adherends, and also has the (dehydration) effect of removingmoisture contained in the curable composition. The silane coupling agentis also a compound that not only has the above-mentioned effects butalso has a possibility of functioning as a physical property modifier, adispersibility-improving agent of inorganic fillers, or the like.

As the hydrolyzable silyl group in the silane coupling agent (D), theremay be mentioned those groups represented by the formula (2): —SiR¹_(n)X¹ _(3-n) wherein X¹ is a hydrolyzable group.

More specifically, there may be mentioned those groups describedhereinabove as hydrolyzable groups. Among those, a methoxy group, anethoxy group and like groups are preferred from the appropriatehydrolysis rate viewpoint. The number of hydrolyzable groups containedin one molecule of the silane coupling agent is preferably not smallerthan 2, and particularly preferably not smaller than 3.

Examples of the functional group in the silane coupling agent (D), otherthan the hydrolyzable silyl group, include a substituted orunsubstituted amino group, mercapto group, epoxy group, carboxyl group,vinyl group, isocyanato group and isocyanurate group, halogen atoms, andthe like. The silane coupling agent having a substituted orunsubstituted amino group is preferable among them because of itsfavorable solubility with the amidine compound (B) and the like. Thesilane coupling agent having a substituted or unsubstituted amino groupis preferable also in that it improves the adhesiveness between theobtained cured products and adherends.

When the solubility is insufficient upon dissolving the amidine compound(B) in the sulfonyl group-containing compound (C), it is possible toimprove the solubility by using the silane coupling agent (D) incombination. Further, the addition of the silane coupling agent leads tofavorable storage stability of the mixture.

Further, curable compositions obtained by mixing the above-mentionedmixture with the reactive silyl group-containing organic polymer (A) canbe favorably stored for a long period of time because a viscosityincrease over time is suppressed.

The silane coupling agent (D) is not particularly restricted butincludes aminosilanes such as γ-aminopropyltrimethoxysilane,γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane,γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane,γ-(2-aminoethyl)aminopropyltrimethoxysilane,γ-(2-aminoethyl)aminopropylmethyldimethoxysilane,γ-(2-aminoethyl)aminopropyltriethoxysilane,γ-(2-aminoethyl)aminopropylmethyldiethoxysilane,γ-(2-aminoethyl)aminopropyltriisopropoxysilane,γ-(2-(2-aminoethyl)aminoethyl)aminopropyltrimethoxysilane,γ-(6-aminohexyl)aminopropyltrimethoxysilane,3-(N-ethylamino)-2-methylpropyltrimethoxysilane,2-aminoethylaminomethyltrimethoxysilane,N-cyclohexylaminomethyltriethoxysilane,N-cyclohexylaminomethyldiethoxymethylsilane,γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane,N-phenyl-γ-aminopropyltrimethoxysilane,N-phenylaminomethyltrimethoxysilane,N-benzyl-γ-aminopropyltrimethoxysilane,N-vinylbenzyl-γ-aminopropyltriethoxysilane,N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole,N-cyclohexylaminomethyltriethoxysilane,N-cyclohexylaminomethyldiethoxymethylsilane,N-phenylaminomethyltrimethoxysilane,(2-aminoethyl)aminomethyltrimethoxysilane andN,N′-bis[3-(trimethoxysilyl)propyl]ethylenediamine; ketimine typesilanes such asN-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, andcondensation products resulting from partial condensation of the silanesmentioned above.

From the viewpoints of compatibility, transparency, and availability,γ-aminopropyltrimethoxysilane is particularly preferable among theabove-mentioned silane coupling agents (D).

Either a single species among the silane coupling agents (D) may beincorporated in the curable composition or a combination of a pluralitythereof may be incorporated in the curable composition. Upon selectingthe silane coupling agent, for the purpose of preventing the surfacecurability of the curable composition from changing during storage, itis preferable to use a silane coupling agent having a hydrolyzable groupof the same structure as that of the hydrolyzable group in the organicpolymer (A). That is, when the hydrolyzable silyl group of the organicpolymer (A) is a methoxysilyl group, the silane coupling agent (D)having a structure of the methoxysilyl group is selected. When thehydrolyzable silyl group of the organic polymer (A) is an ethoxysilylgroup, the silane coupling agent (D) having a structure of theethoxysilyl group is selected.

As a method of blending the amidine compound (B), the sulfonylgroup-containing compound (C), and the silane coupling agent (D), thefollowing can be carried out. Namely, the three may be mixed togetherand then added; or the amidine compound (B) may be mixed in advance withthe sulfonyl group-containing compound (C), and thereto added the silanecoupling agent (D). Particularly in the case of using, as the sulfonylgroup-containing compound (C), such a compound asalkylbenzenesulfonamide, the latter method improves the solubility ofthe amidine compound (B).

The silane coupling agent (D) maybe used in combination with the amidinecompound (B) and the sulfonyl group-containing compound (C), or may besingly used.

The blending level of the silane coupling agent (D) is preferably 0.01to 20 parts by weight, more preferably 0.1 to 10 parts by weight, andparticularly preferably 1 to 7 parts by weight, per 100 parts by weightof the organic polymer (A). When the blending level thereof is below0.01 parts by weight, the storage stability of the curable compositiontends to be inferior, and the adhesiveness of the obtained curedproducts tends to be inferior. On the other hand, when the blendinglevel thereof is in excess of 20 parts by weight, any practical depthcurability of the curable composition tends not to be obtained.

A plasticizer can be added, if necessary, to the curable composition ofthe present invention. The plasticizer functions as an agent foradjusting the viscosity and slump properties of the curable compositionand adjusting the tensile strength, elongation property and likemechanical properties of the cured products obtained.

The plasticizer is not particularly restricted but includes: phthalateesters such as dibutyl phthalate, diheptyl phthalate,bis(2-ethylhexyl)phthalate, and butyl benzyl phthalate; nonaromaticdibasic acid esters such as dioctyl adipate, dioctyl sebacate, dibutylsebacate, and isodecyl succinate; aliphatic esters such as butyl oleateand methyl acetyl ricinoleate; phosphoric acid esters such as tricresylphosphate and tributyl phosphate; trimellitic acid esters; chlorinatedparaffins; hydrocarbon type oils such as alkyldiphenyl and partiallyhydrogenated terphenyl; process oils; epoxy type plasticizers such asepoxidized soybean oil and benzyl epoxystearate; and the like.

Addition of a polymeric plasticizer containing a polymer component inthe molecule is preferred since such addition makes it possible tomaintain the initial properties of the cured products obtained for along period of time and, further, improve the drying properties (alsoreferred to as applicability) of an alkyd paint when it is applied tothe cured products obtained. The polymeric plasticizer is notparticularly restricted but includes: vinyl polymers obtained bypolymerization of vinyl monomers by various methods; polyalkylene glycolesters such as diethylene glycol dibenzoate, triethylene glycoldibenzoate and pentaerythritol esters; polyester type plasticizersderived from a dibasic acid such as sebacic acid, adipic acid, azelaicacid and phthalic acid and a dihydric alcohol such as ethylene glycol,diethylene glycol, triethylene glycol, propylene glycol and dipropyleneglycol; polyether polyols such as polyethylene glycol, polypropyleneglycol and polytetramethylene glycol, each having a molecular weight ofnot lower than 500, preferably not lower than 1000, or polyetherderivatives derived from such polyether polyols by esterification oretherification of one or more hydroxyl groups therein; polystyrenes suchas polystyrene and poly-α-methylstyrene; polybutadiene, polybutene,polyisobutylene, butadiene-acrylonitrile copolymers, polychloroprene andthe like.

Among these polymeric plasticizers, those highly compatible with theorganic polymer (A) are preferred and, for example, polyethers and vinylpolymers may be mentioned. Polyethers are more preferred since theyprovide the curable composition with good surface curability and depthcurability and cause no curing retardation after storage; morespecifically, polypropylene glycol is particularly preferred.

Further, vinyl polymers are preferred since they have high compatibilitywith the organic polymer (A) and provide the resulting cured productswith good weather resistance and thermal stability; among them, acrylicpolymers and/or methacrylic polymers are more preferred, and suchacrylic polymers as polyacrylic acid alkyl esters are particularlypreferred.

While the method of producing the polyacrylic acid alkyl esters is notparticularly restricted, the living radical polymerization method ispreferred because of its capability of giving polymers narrow inmolecular weight distribution and possibly low in viscosity, and theatom transfer radical polymerization method is more preferred. Alsoparticularly preferred is the method called “SGO process” and disclosedin Japanese Kokai Publication 2001-207157, which comprises continuouslybulk-polymerizing an acrylic acid alkyl ester type compound underhigh-temperature and high-pressure conditions.

The number average molecular weight of the polymeric plasticizer is 500to 15000, preferably 800 to 10000, more preferably 1000 to 8000,particularly preferably 1000 to 5000, and most preferably 1000 to 3000.When the molecular weight of the polymeric plasticizer is too low, theplasticizer may escape from the cured products obtained with the lapseof time due to heat or rainfall and, as a result, it cannot maintain theinitial physical properties over a long period of time, staining byadhesion of dust may possibly be caused and the alkyd applicabilitytends to become poor. On the other hand, when the molecular weight isexcessively high, the viscosity of the curable composition will increaseand the workability tends to become poor.

The molecular weight distribution of the polymeric plasticizer is notparticularly restricted but preferably is narrow, for example narrowerthan 1.80, preferably not wider than 1.70, more preferably not widerthan 1.60, still more preferably not wider than 1.50, particularlypreferably not wider than 1.40, and most preferably not wider than 1.30.

In the case of polyether type polymers, the number average molecularweight is determined by the end-group analysis and, in the case of otherpolymers, it is determined by the GPC method. The molecular weightdistribution (Mw/Mn) is measured by the GPC method (on the polystyreneequivalent basis).

The polymeric plasticizer may be a reactive silyl group-containing oneor a reactive silyl group-free one; a reactive silyl group-containingpolymeric plasticizer is preferably added, however, since the polymericplasticizer is involved in the curing reaction and thus, the plasticizercan be prevented from migrating from the cured products obtained.

The reactive silyl group-containing polymeric plasticizer is preferablya compound whose reactive silyl group content is, on an average, notmore than one, and more preferably not more than 0.8, per molecule. Whena reactive silyl group-containing plasticizer, in particular a reactivesilyl group-containing oxyalkylene polymer, is added, it is preferredthat the number average molecular weight thereof be lower than that ofthe organic polymer (A) so that a satisfactory plasticizing effect maybe obtained.

The plasticizer to be added may include a single species or acombination of a plurality of species. It is also possible to add alow-molecular-weight plasticizer and a polymeric plasticizer incombination. The plasticizer addition may also be made on the occasionof the production of the organic polymer (A).

The addition level thereof is preferably 5 to 150 parts by weight, morepreferably 10 to 120 parts by weight, and particularly preferably 20 to100 parts by weight, per 100 parts by weight of the organic polymer (A).At addition levels lower than 5 parts by weight, there is a tendency forthe plasticizing effect to be little produced and, at levels exceeding150 parts by weight, there arises a tendency for the mechanical strengthof the cured products to become insufficient.

For example, an epoxy resin, a phenol resin, sulfur, alkyl titanates,aromatic polyisocyanate, and the like can be added, if necessary, to thecurable composition of the present invention in order to give anadhesiveness-imparting effect. These may be added singly or a pluralitythereof may be added in combination. However, since increase in theaddition level of the epoxy resin tends to lower the catalytic activityof the amidine compound (B), the addition level of the epoxy resin ispreferably small.

The addition level of the epoxy resin is preferably not higher than 5parts by weight, and more preferably not higher than 0.5 parts byweight, per 100 parts by weight of the organic polymer (A); substantialabsence thereof is particularly preferred.

Carboxylic acids are added as a promoter, if necessary, to the curablecomposition of the present invention, to the extent that the effects ofthe invention are not impaired.

The carboxylic acids used as a promoter are not particularly restrictedbut include: straight-chain saturated fatty acids such as acetic acid,propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid,caprylic acid, 2-ethylhexanoic acid, pelargonic acid, capric acid,undecanoic acid, lauric acid, tridecylic acid, myristic acid,pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid,nonadecanoic acid, arachic acid, behenic acid, lignoceric acid, ceroticacid, montanic acid, melissic acid and lacceric acid; monoenoicunsaturated fatty acids such as undecylenic acid, linderic acid, tsuzuicacid, physeteric acid, myristoleic acid, 2-hexadecenoic acid,6-hexadecenoic acid, 7-hexadecenoic acid, palmitoleic acid, petroselinicacid, oleic acid, elaidic acid, asclepic acid, vaccenic acid, gadoleicacid, gondoic acid, cetoleic acid, erucic acid, brassidic acid,selacholeic acid, ximenic acid, lumequeic acid, acrylic acid,methacrylic acid, angelic acid, crotonic acid, isocrotonic acid and10-undecenoic acid; polyenoic unsaturated fatty acids such aslinoelaidic acid, linolic acid, 10,12-octadecadienoic acid, hiragonicacid, α-eleostearic acid, β-eleostearic acid, punicic acid, linolenicacid, 8,11,14-eicosatrienoic acid, 7,10,13-docosatrienoic acid,4,8,11,14-hexadecatetraenoic acid, moroctic acid, stearidonic acid,arachidonic acid, 8,12,16,19-docosatetraenoic acid,4,8,12,15,18-eicosapentaenoic acid, clupanodonic acid, nisinic acid anddocosahexaenoic acid; branched fatty acids such as 1-methylbutyric acid,isobutyric acid, 2-ethylbutyric acid, isovaleric acid, tuberculostearicacid, pivalic acid, 2,2-dimethylbutyric acid, 2-ethyl-2-methylbutyricacid, 2,2-diethylbutyric acid, 2,2-dimethylvaleric acid,2-ethyl-2-methylvaleric acid, 2,2-diethylvaleric acid,2,2-dimethylhexanoic acid, 2,2-diethylhexanoic acid,2,2-dimethyloctanoic acid, 2-ethyl-2,5-dimethylhexanoic acid,neodecanoic acid and versatic acid; triple bond-containing fatty acidssuch as propiolic acid, tariric acid, stearolic acid, crepenynic acid,xymenynic acid and 7-hexadecynoic acid; alicyclic carboxylic acids suchas naphthenic acid, malvalic acid, sterculic acid, hydnocarpic acid,chaulmoogric acid, gorlic acid, 1-methylcyclopentanecarboxylic acid,1-methylcyclohexanecarboxylic acid,2-methylbicyclo[2.2.1]-5-heptene-2-carboxylic acid,1-adamantanecarboxylic acid, bicycle[2.2.1]heptane-1-carboxylic acid andbicycle[2.2.2]octane-1-carboxylic acid; oxygen-containing fatty acidssuch as acetoacetic acid, ethoxyacetic acid, glyoxylic acid, glycolicacid, gluconic acid, sabinic acid, 2-hydroxytetradecanoic acid, ipurolicacid, 2,2-dimethyl-3-hydroxypropionic acid, 2-hydroxyhexadecanoic acid,jalapinolic acid, juniperic acid, ambrettolic acid, aleuritic acid,2-hydroxyoctadecanoic acid, 12-hydroxyoctadecanoic acid,18-hydroxyoctadecanoic acid, 9,10-dihydroxyoctadecanoic acid, ricinolicacid, camlolenic acid, licanic acid, pheronic acid, cerebronic acid and2-methyl-7-oxabicyclo[2.2.1]-5-heptene-2-carboxylic acid; andhalogen-substituted monocarboxylic acids such as chloroacetic acid,2-chloroacrylic acid and chlorobenzoic acid. As far as aliphaticdicarboxylic acids are concerned, there may be mentioned saturateddicarboxylic acids such as adipic acid, azelaic acid, pimelic acid,suberic acid, sebacic acid, ethylmalonic acid, glutaric acid, oxalicacid, malonic acid, succinic acid, oxydiacetic acid, dimethylmalonicacid, ethylmethylmalonic acid, diethylmalonic acid, 2,2-dimethylsuccinicacid, 2,2-diethylsuccinic acid, 2,2-dimethylglutaric acid and1,2,2-trimethyl-1,3-cyclopentanedicarboxylic acid; and unsaturateddicarboxylic acids such as maleic acid, fumaric acid,acetylenedicarboxylic acid and itaconic acid. As far as aliphaticpolycarboxylic acids are concerned, there may be mentioned tricarboxylicacids such as aconitic acid, 4,4-dimethylaconitic acid, citric acid,isocitric acid and 3-methylisocitric acid. As aromatic carboxylic acids,there may be mentioned aromatic monocarboxylic acids such as benzoicacid, 9-anthracenecarboxylic acid, atrolactic acid, anisic acid,isopropylbenzoic acid, salicylic acid and toluic acid; and aromaticpolycarboxylic acids such as phthalic acid, isophthalic acid,terephthalic acid, carboxyphenylacetic acid and pyromellitic acid; andso forth. The combined use of these promoters is expected to increasethe catalytic activity of the curing agent and improve such propertiesas curability and depth curability of the curable composition.

The carboxylic acids mentioned above are preferably used in an amount of0.01 to 20 parts by weight, and more preferably 0.1 to 10 parts byweight, per 100 parts by weight of the organic polymer (A).

To the curable composition of the present invention, there can be addeda filler, if necessary. The filler is not particularly restricted butincludes: reinforcing fillers such as fumed silica, precipitated silica,crystalline silica, fused silica, dolomite, silicic anhydride, hydroussilicic acid and carbon black; heavy calcium carbonate, colloidalcalcium carbonate, magnesium carbonate, diatomaceous earth, calcinedclay, clay, talc, titanium oxide, bentonite, organic bentonite, ferricoxide, fine aluminum powder, flint powder, zinc oxide, activated zincwhite, shirasu balloons, glass microballoons, organic microballoonsbased on a phenol resin or a vinylidene chloride resin, organic powderssuch as PVC powder and PMMA powder; and fibrous fillers such asasbestos, glass fibers and filaments.

When a filler is added, the addition level thereof is preferably 1 to250 parts by weight, and more preferably 10 to 200 parts by weight, per100 parts by weight of the organic polymer (A).

On the occasion of using the curable composition as a one-pack typeadhesive or sealant, it is preferred, for obtaining good storagestability, that such a filler as mentioned above be uniformly mixed witha dehydrating agent such as calcium oxide and the mixture be allowed tostand in a sealed bag made of an airtight material for a proper periodof time for dehydrating and drying, and then used, as disclosed inJapanese Kokai Publication 2001-181532 and the like.

When the cured products obtained are to be used in the fields ofapplication where transparency is required, a polymer powder made of apolymer of methyl methacrylate and the like, and noncrystalline silica,as disclosed in Japanese Kokai Publication H11-302527 and the like, arepreferred as the filler to be added; hydrophobic silica and the like, asdisclosed in Japanese Kokai Publication 2000-38560 and the like, aremore preferred.

The hydrophobic silica, so referred to herein, is a product derived bytreating the surface of the silicon dioxide fine powder generallyoccupied by silanol (—SiOH) groups with an organosilicon halide, analcohol or the like for conversion of those groups to (—SiO-hydrophobicgroups). The hydrophobic silica is not particularly restricted butincludes, for example, products obtained by treating silanol groupsoccurring on the surface of a silicon dioxide fine powder withdimethylsiloxane, hexamethyldisilazane, dimethyldichlorosilane,trimethoxyoctylsilane, trimethylsilane, or the like. The untreatedsilicon dioxide fine powder whose surface is occupied by silanol (—SiOH)groups is called hydrophilic silica fine powder.

When the cured products obtained are to be used in the fields ofapplication where high strength is required, silicon compounds such asfumed silica, precipitated silica, crystalline silica, fused silica,dolomite, silicic anhydride and hydrous silicic acid; carbon black,surface-treated finely divided calcium carbonate, calcined clay, clay,activated zinc white and the like are preferred as the filler to beadded, and the addition level thereof is preferably 1 to 200 parts byweight per 100 parts by weight of the organic polymer (A).

Further, when the cured products obtained are to be used in the fieldsof application where low strength and high elongation modulus arerequired, titanium oxide, calcium carbonate such as heavy calciumcarbonate, magnesium carbonate, talc, ferric oxide, zinc oxide andshirasu balloons are preferred as the filler to be added, and theaddition level thereof is preferably 5 to 200 parts by weight per 100parts by weight of the organic polymer (A).

When calcium carbonate is added, the tendency toward improvements in thebreaking strength, breaking elongation and adhesiveness of the curedproducts obtained increases as the specific surface area increases. Onlyone of these filler species may be added or a plurality of speciesthereof may be added in combination.

The example of addition of a plurality of additives is not particularlyrestricted but the combined use of a surface-treated fine calciumcarbonate and a calcium carbonate larger in particle diameter such asheavy calcium carbonate is preferred since cured products excellent inphysical properties can be obtained.

Preferred as the surface-treated fine calcium carbonate are those whoseparticle diameter is not larger than 0.5 μm and whose particle surfacehas been treated with fatty acids or fatty acid salts.

Preferred as the calcium carbonate having a large particle diameter arethose whose particle diameter is not smaller than 1 μm and whoseparticle surface has not been treated.

In cases where the curable composition is required to have goodworkability (releasability, etc.) or where the surface of the curedproducts obtained is required to be matted, organic balloons orinorganic balloons are preferred as the filler to be added. Thesefillers may be surface-treated or non-surface-treated, and only onespecies thereof may be added or a plurality of species thereof may beadded in admixture. For improving the workability (releasability, etc.),the particle diameter of the balloons is preferably not larger than 0.1mm and, for rendering the cured product surface matted, it is preferably5 to 300 μm.

The curable composition of the present invention, which gives curedproducts excellent in chemical resistance, is suited for use, inparticular, as a sealant, adhesive or like composition for siding boardsin ceramic and like systems and for housing outside-wall joints andoutside-wall tiles.

On the occasion of use in such fields of application, the cured productsobtained appear or exist on the joints or like observable surfaces and,therefore, it is desirable that the cured product design be in harmonywith the outside-wall design. In recent years, in particular, thesputtering coating and the addition of colored aggregates, among others,have been employed for providing luxurious outside walls, so that thedesigns of cured products are becoming more and more important.

For obtaining luxurious designs, a scaly or granular substance isincorporated in the curable composition of the present invention. Theaddition of a granular substance gives sandy or sandstone-like roughsurfaces, and the addition of a scaly substance gives surfaces rendereduneven due to scales.

The cured products obtained are in harmony with luxurious outside wallsand are excellent in chemical resistance, so that the luxuriousappearance thereof can be maintained for a long period of time.

The scaly or granular substance is not particularly restricted butincludes, for example, one disclosed in Japanese Kokai PublicationH09-53063, and the diameter thereof is properly selected according tothe outside-wall material and design and the like, and is preferably notsmaller than 0.1 mm, and more preferably 0.1 to 5.0 mm. In the case of ascaly substance, the thickness of scales is preferably 1/10 to ⅕ (0.01to 1.00 mm) of the diameter.

The addition level of the scaly or granular substance is properlyselected according to the size of the scaly or granular substance, theoutside-wall material and design and other factors; preferably, theaddition level is 1 to 200 parts by weight per 100 parts by weight ofthe curable composition.

The material of the scaly or granular substance is not particularlyrestricted but includes natural products such as silica sand and mica,synthetic rubbers, synthetic resins, and inorganic materials such asalumina. These may be appropriately colored according to theoutside-wall material and design and so forth so that the design qualityof the composition applied to joints and so forth may be enhanced.

Preferred methods of finishing are those disclosed in Japanese KokaiPublication H09-53063 and the like.

The scaly or granular substance may be incorporated in advance in thecurable composition or may be admixed with the curable composition ofthe occasion of use thereof.

It is also possible, for the same purposes, to add balloons (preferablyhaving an average particle diameter of not smaller than 0.1 mm) to thecurable composition, thereby providing the resulting cured productsurface with a coarse feel such as a sandy or sandstone feel and,further, contributing to weight reduction. The “balloons” are sphericalhollow fillers.

The balloons are not particularly restricted but include, for example,those disclosed in Japanese Kokai Publications H10-251618, H02-129262,H04-8788, H04-173867, 1405-1225, H07-113073, H09-53063, 2000-154368 and2001-164237 and WO 97/05201.

As the material of balloons, there may be mentioned inorganic materialssuch as glass, shirasu and silica; and organic materials such as phenolresins, urea resins, polystyrene and Saran. Mention may further be madeof composite materials of an inorganic material and an organic material;and laminates comprising a plurality of layers. These may be used singlyor a plurality of species thereof may be used in combination.

It is also possible to use balloons subjected to surface coatingtreatment, treatment with various surface treatment agents or some othertreatment; as typical examples, there may be mentioned organic balloonscoated with calcium carbonate, talc, titanium oxide or the like, andinorganic balloons surface-treated with an adhesiveness-imparting agent.

Further, the balloons preferably have a particle diameter of not smallerthan 0.1 mm, more preferably 0.2 mm to 5.0 mm, particularly preferably0.5 mm to 5.0 mm. When the diameter is smaller than 0.1 mm, the additioneven in large amounts only increases the viscosity of the composition,sometimes failing to provide the resulting cured products with a coarsefeel.

The addition level of the balloons can be properly selected according tothe intended decorative effect; it is preferred that balloons having aparticle diameter of not smaller than 0.1 mm be added in an amount suchthat the volume concentration thereof in the curable composition amountsto 5 to 25% by volume, more preferably 8 to 22% by volume. When thevolume concentration of balloons is below 5% by volume, the desiredcoarse feel tends to become lost. At level exceeding 25% by volume, theviscosity of the curable composition increases and the workabilitythereof tends to become poor; further, the modulus of the cured productsincreases and the fundamental performance characteristics of the sealantor adhesive tend to become impaired.

On the occasion of adding balloons, it is also possible to add, incombination, such an anti-slip agent as the one disclosed in JapaneseKokai Publication 2000-154368 or such an amine compound capable ofrendering the resulting cured product surface uneven and matted as theone disclosed in Japanese Kokai Publication 2001-164237. Preferred asthe amine compound mentioned above are primary and/or secondary amineshaving a melting point of 35° C. or higher.

Also usable as the balloons are thermally expandable minute hollowparticles disclosed in Japanese Kokai Publication 2004-51701 or2004-66749, for instance. The “thermally expandable minute hollowparticles” are spherical plastic bodies made of a polymer shell material(vinylidene chloride type copolymer, acrylonitrile type copolymer orvinylidene chloride-acrylonitrile copolymer) with a low-boiling compoundsuch as a C₁₋₅ hydrocarbon as spherically enclosed therein.

By adding thermally expandable minute hollow particles to the curablecomposition of the present invention, it becomes possible to obtain anadhesive composition which, when no more required, can be peeled offwith ease only by heating without destruction of the adherend materials,and can be thermally removed without using any organic solvent at all.This is based on the mechanism such that when the adhesive portion isheated, the gas pressure inside the shells of the thermally expandableminute hollow particles increases and the polymer shell material issoftened and dramatically expanded to cause peeling at the adhesiveinterface.

When the curable composition of the present invention containssealant-cured particles as well, the cured products obtained can have anuneven rough surface and, thus, the decorative feature thereof can beimproved. The preferred diameter, blending level, material and the likeof the sealant-cured particles are disclosed in Japanese KokaiPublication 2001-115142, and the diameter is preferably 0.1 to 1 mm,more preferably 0.2 to 0.5 mm. The blending level is preferably 5 to 100parts by weight, and more preferably 20 to 50 parts by weight, per 100parts by weight of the curable composition. The material is notparticularly restricted provided it is one of the materials used insealing compositions; thus, mention may be made of urethane resins,silicones, modified silicones and polysulfide rubbers, for example.Among those mentioned above, modified silicone type sealant-curedparticles are preferred.

To the curable composition of the present invention, there can be addeda silicate, if necessary. The silicate acts as a crosslinking agent onthe organic polymer (A) and consequently functions to bring aboutimprovements in the restorability, durability and creep resistance ofthe cured products obtained.

Further, the addition of a silicate brings about improvements in theadhesiveness and water-resistant adhesiveness, and the bond durabilityunder high-temperature and high-humidity conditions, of the curedproducts obtained. The silicate is not particularly restricted butincludes, for example, tetraalkoxysilanes or partial hydrolysiscondensation products derived therefrom; more specifically, there may bementioned tetraalkoxysilanes (tetraalkyl silicates) such astetramethoxysilane, tetraethoxysilane, ethoxytrimethoxysilane,dimethoxydiethoxysilane, methoxytriethoxysilane, tetra-n-propoxysilane,tetra-i-propoxysilane, tetra-n-butoxysilane, tetra-i-butoxysilane andtetra-t-butoxysilane as well as partial hydrolysis condensation productsderived therefrom.

The addition level of the silicate is preferably 0.1 to 20 parts byweight, and more preferably 0.5 to 10 parts by weight, per 100 parts byweight of the organic polymer (A).

The tetraalkoxysilane-derived partial hydrolysis condensation productmentioned above is not particularly restricted but includes, forexample, products derived from tetraalkoxysilanes by addition of waterthereto to cause partial hydrolysis and condensation.

The addition of a tetraalkoxysilane-derived partial hydrolysiscondensation product to the curable composition is preferred since suchcondensation product produces significant improvements in restorability,durability and creep resistance of the cured products obtained ascompared with the corresponding composition containing atetraalkoxysilane added thereto.

Commercially available as the tetraalkoxysilane-derived partialhydrolysis condensation product are, for example, Methyl Silicate 51 andEthyl Silicate 40 (both being products of Colcoat Co., Ltd.); these canbe used as additives.

For the purpose of inhibiting the surface curability of the curablecomposition from changing during storage, it is preferred that thesilicate be selected from among those in which the silicon atom-boundhydrolyzable groups are the same as the hydrolyzable groups in thereactive silyl group occurring in the organic polymer (A). Thus, whenthe organic polymer (A) contains methoxysilyl groups, a methoxysilylgroup-containing silicate is preferably selected and, when the organicpolymer (A) contains ethoxysilyl groups, an ethoxysilyl group-containingsilicate is preferably selected.

Addition of a polymeric plasticizer containing a polymer component inthe molecule is preferred since such addition makes it possible tomaintain the initial properties of the cured products obtained for along period of time and, further, improve the drying properties (alsoreferred to as applicability) of an alkyd paint when it is applied tothe cured products obtained.

The polymeric plasticizer is not particularly restricted but includes:vinyl polymers obtained by polymerization of vinyl monomers by variousmethods; polyalkylene glycol esters such as diethylene glycoldibenzoate, triethylene glycol dibenzoate and pentaerythritol esters;polyester type plasticizers derived from a dibasic acid such as sebacicacid, adipic acid, azelaic acid and phthalic acid and a dihydric alcoholsuch as ethylene glycol, diethylene glycol, triethylene glycol,propylene glycol and dipropylene glycol; polyether polyols such aspolyethylene glycol, polypropylene glycol and polytetramethylene glycol,each having a molecular weight of not lower than 500, preferably notlower than 1000, or polyether derivatives derived from such polyetherpolyols by esterification or etherification of one or more hydroxylgroups therein; polystyrenes such as polystyrene andpoly-α-methylstyrene; polybutadiene, polybutene, polyisobutylene,butadiene-acrylonitrile copolymers, polychloroprene and the like.

In the curable composition of the present invention, there can beincorporated a tackifier, if necessary. The tackifier resin is notparticularly restricted provided that it is one in common use,irrespective of whether it occurs as a solid or liquid at ordinarytemperature. For example, there may be mentioned styrene blockcopolymers, hydrogenation products derived therefrom, phenol resins,modified phenol resins (e.g. cashew oil-modified phenol resins, talloil-modified phenol resins), terpene phenol type resins, xylene-phenoltype resins, cyclopentadiene-phenol type resins, coumarone-indene typeresins, rosin type resins, rosin ester type resins, hydrogenated rosinester type resins, xylene type resins, low-molecular-weight polystyrenetype resins, styrene copolymer resins, petroleum resins (e.g. C5hydrocarbon type resins, C9 hydrocarbon type resins, C5C9 hydrocarboncopolymer resins), hydrogenated petroleum resins, terpene type resins,DCPD resin petroleum resins. These may be added singly or a pluralitythereof may be added in combination.

The styrene block copolymers and hydrogenation products derivedtherefrom mentioned above are not particularly restricted but include,for example, styrene-butadiene-styrene block copolymers (SBSs),styrene-isoprene-styrene block copolymers (SISs),styrene-ethylenebutylene-styrene block copolymers (SEBSs),styrene-ethylenepropylene-styrene block copolymers (SEPSs) andstyrene-isobutylene-styrene block copolymers (SEBSs).

The addition level of the tackifier is preferably 5 to 1,000 parts byweight, and more preferably 10 to 100 parts by weight, per 100 parts byweight of the organic polymer (A).

In the curable composition of the present invention, there can beincorporated a solvent or diluent, if necessary. The solvent or diluentis not particularly restricted but includes, for example, aliphatichydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, halogenatedhydrocarbons, alcohols, esters, ketones and ethers. These may be addedsingly or a plurality thereof may be added in combination.

When a solvent or diluent is added, the solvent or diluent preferablyhas a boiling point of 150° C. or higher, and more preferably 200° C. orhigher, so that the volatile components may be inhibited fromdissipating into the air on the occasion of indoor use of the curablecomposition. In the curable composition of the present invention, theremay be incorporated a physical property modifier, if necessary. Thephysical property modifier functions so as to adjust the tensileproperties and hardness of the resulting cured products. The physicalproperty modifier is not particularly restricted but includes, forexample, alkylalkoxysilanes such as methyltrimethoxysilane,dimethyldimethoxysilane, trimethylmethoxysilane andn-propyltrimethoxysilane; alkylisopropenoxysilanes such asdimethyldiisopropenoxysilane, methyltriisopropenoxysilane andγ-glycidoxypropylmethyldiisopropenoxysilane; functional group-containingalkoxysilanes such as γ-glycidoxypropylmethyldimethoxysilane,γ-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane,vinyldimethylmethoxysilane, γ-aminopropyltrimethoxysilane,N-(β-aminoethyl)aminopropylmethyldimethoxysilane,γ-mercaptopropyltrimethoxysilane andγ-mercaptopropylmethyldimethoxysilane; silicone varnishes; andpolysiloxanes. These may be added singly or a plurality thereof may beadded in admixture.

Among such physical property modifiers, those which form, uponhydrolysis, a compound containing a monovalent silanol group in themolecule are preferred since they are effective in reducing the modulusof the resulting cured products without worsening the surface stickinessthereof; among them, those which form, upon hydrolysis, trimethylsilanolare more preferred.

The compounds which form, upon hydrolysis, a compound containing amonovalent silanol group in the molecule are not particularly restrictedbut include: those compounds disclosed in Japanese Kokai PublicationH05-117521; compounds derived from an alkyl alcohol such as hexanol,octanol and decanol, and capable of forming, upon hydrolysis, such anorganosilicon compound represented by R₃SiOH as trimethylsilanol; andthose compounds disclosed in Japanese Kokai Publication H11-241029 whichare compounds derived from a polyhydric alcohol containing 3 or morehydroxyl groups in each molecule, for example trimethylolpropane,glycerol, pentaerythritol or sorbitol, and capable of forming, uponhydrolysis, such an organosilicon compound represented by R₃SiOH astrimethylsilanol.

Further, mention may be made of those compounds disclosed in JapaneseKokai Publication H07-258534 which are derived from an oxypropylenepolymer and capable of forming, upon hydrolysis, such an organosiliconcompound represented by R₃SiOH as trimethylsilanol and, further, thosecompounds disclosed in Japanese Kokai Publication H06-279693 whichcontain a crosslinkable hydrolyzable silyl group and a silyl groupcapable of forming, upon hydrolysis, a monovalent silanolgroup-containing compound.

The addition level of the physical property modifier is preferably 0.1to 20 parts by weight, and more preferably 0.5 to 10 parts by weight,per 100 parts by weight of the organic polymer (A).

In the curable composition of the present invention, there may beincorporated a thixotropic agent (anti-sagging agent), if necessary. Theterm “thixotropic agent” refers to an agent functioning to prevent thecurable composition from sagging and improve the workability thereof.

The thixotropic agent is not particularly restricted but includes, forexample, polyamide waxes; hydrogenated castor oil derivatives; and metalsoaps such as calcium stearate, aluminum stearate and barium stearate.Further, mention may be made of those rubber powders having a particlediameter of 10 to 500 μm which are disclosed in Japanese KokaiPublication H11-349916, and those organic fibers disclosed in JapaneseKokai Publication 2003-155389. These thixotropic agents (anti-saggingagents) may be added singly or a plurality of species may be added incombination.

The addition level of the thixotropic agent is preferably 0.1 to 20parts by weight per 100 parts by weight of the organic polymer (A).

In the curable composition of the present invention, there can beincorporated a compound containing an epoxy group in each molecule, ifnecessary. By adding an epoxy group-containing compound, it becomespossible to enhance the restorability of the cured products obtained.

The epoxy group-containing compound is not particularly restricted butincludes, for example, epoxidized unsaturated fats and oils; epoxidizedunsaturated fatty acid esters; alicyclic epoxy compounds;epichlorohydrin derivatives and like compounds; and mixtures thereof.More specifically, there may be mentioned epoxidized soybean oil,epoxidized linseed oil,bis(2-ethylhexyl)-4,5-epoxycyclohexane-1,2-dicarboxylate (E-PS),epoxyoctyl stearate, epoxybutyl stearate and the like. Among these, E-PSis preferred.

The addition level of the epoxy compound is preferably 0.5 to 50 partsby weight per 100 parts by weight of the organic polymer (A).

In the curable composition of the present invention, there can be addeda photocurable substance, if necessary. The photocurable substance is asubstance capable of undergoing, under the action of light, chemicalchanges in molecular structure in a short period of time which lead tochanges in physical properties such as curing. The addition of aphotocurable substance to the curable composition results in theformation of a photocurable substance-based layer on the surface of thecured products obtained and thus in improvements in the stickiness andweather resistance of the cured products.

The photocurable substance is not particularly restricted but includesthose known in the art, such as organic monomers, oligomers and resins,and compositions containing any of them; for example, there may bementioned unsaturated acrylic compounds, vinyl cinnamate polymers andazidized resins.

As the unsaturated acrylic compounds, there may be mentioned monomers,oligomers, or mixtures thereof, containing one or a plurality of acrylicor methacrylic unsaturated groups in each molecule, and, specifically,propylene (or butylene or ethylene) glycol di(meth)acrylate, neopentylglycol di(meth)acrylate and like monomers or oligoesters thereof havinga molecular weight not exceeding 10,000. More specifically, there may bementioned, for example, such special acrylates as (bifunctional) AronixM-210, Aronix M-215, Aronix M-220, Aronix M-233, Aronix M-240 and AronixM-245; (trifunctional) Aronix M-305, Aronix M-309, Aronix M-310, AronixM-315, Aronix M-320 and Aronix M-325; and (polyfunctional) Aronix M-400(all Aronix products being available from Toagosei Co., Ltd.). Amongthese, acrylic functional group-containing compounds are preferred, andcompounds containing, on an average, 3 or more acrylic functional groupsin each molecule are more preferred.

The vinyl cinnamate polymers include photosensitive resins havingcinnamoyl groups as photosensitive groups, which are compounds resultingfrom esterification of polyvinyl alcohol with cinnamic acid, and manyother derivatives of vinyl cinnamate polymers.

The azidized resins are known as photosensitive resins in which azidegroups are photosensitive groups and include rubber photosensitivesolutions generally containing a diazide compound added as aphotosensitizer and, further, those detailed examples are described in“Kankosei Jushi (Photosensitive Resins)” (published Mar. 17, 1972 byInsatsu Gakkai Shuppanbu Ltd., p. 93 ff., p. 106 ff., and p. 117 ff.).These may be used either singly or in admixture, if necessary togetherwith a sensitizer.

In some cases, the addition of a sensitizer such as ketones and a nitrocompound or an accelerator such as amines enhances the effect.

The addition level of the photocurable substance is preferably 0.1 to 20parts by weight, and more preferably 0.5 to 10 parts by weight, per 100parts by weight of the organic polymer (A). At levels of 0.1 parts byweight or below, the effect of enhancing the weather resistance of thecured products obtained is very little and, at levels of 20 parts byweight or above, the cured products obtained are too hard, tending toundergo cracking or the like.

In the curable composition of the present invention, there can beincorporated an oxygen-curable substance, if necessary. Theoxygen-curable substance can be cured upon reaction with oxygen in theair, and the addition of an oxygen-curable substance makes it possibleto reduce the stickiness of the cured product surface and to preventdirt and dust from adhering to the surface through the formation of acured layer in the vicinity of the cured product surface obtained.

The oxygen-curable substance is not particularly restricted providedthat it is one of the compounds containing an unsaturated compoundcapable of reacting with oxygen in the air; thus, for example, there maybe mentioned drying oils such as tung oil and linseed oil, and variousalkyd resins obtained by modifying such compounds; drying oil-modifiedacrylic polymers, epoxy type resins, silicone type resins; liquidpolymers obtained by polymerizing or copolymerizing such a dienecompound(s) as butadiene, chloroprene, isoprene and 1,3-pentadiene, forexample 1,2-polybutadiene, 1,4-polybutadiene and C5-C8 diene polymers;liquid copolymers obtained by copolymerizing such a diene compound witha vinyl compound, such as acrylonitrile and styrene, copolymerizablewith the diene compound, in a manner such that the diene compound servesas the main component, for example NBR and SBR; and, further, variousmodifications thereof (maleinated modifications, boiled oilmodifications, etc.). Among those mentioned above, tung oil and liquiddiene type polymers are preferred. The oxygen-curable substance to beadded may comprise a single species or a combination of a plurality ofspecies.

When a catalyst and/or metal dryer which are capable of promoting thecuring reaction are added in admixture with the oxygen-curablesubstance, the effect may be enhanced. The catalyst and metal dryer forpromoting the curing reaction are not particularly restricted butinclude, for example, metal salts such as cobalt naphthenate, leadnaphthenate, zirconium naphthenate, cobalt octylate and zirconiumoctylate, and amine compounds.

The addition level of the oxygen-curable substance is preferably 0.1 to20 parts by weight, and more preferably 0.5 to 10 parts by weight, per100 parts by weight of the organic polymer (A). At addition levels below0.1 parts by weight, the effect of improving the stain resistance of thecured products obtained tends to become insufficient and, at levelsexceeding 20 parts by weight, the tensile properties and the like of thecured products obtained tend to become impaired.

Further, the oxygen-curable substance is preferably added in admixturewith a photocurable substance, as disclosed in Japanese KokaiPublication H03-160053.

In the curable composition of the present invention, there can beincorporated an antioxidant, if necessary. By adding an antioxidant, itbecomes possible to enhance the thermal stability of the cured productsobtained.

The antioxidant is not particularly restricted but includes hinderedphenol type, monophenol type, bisphenol type and polyphenol typeantioxidants. Among these, hindered phenol type antioxidants arepreferred. Also preferred are hindered amine type light stabilizers suchas Tinuvin 622LD and Tinuvin 144; Chimassorb 944LD and Chimassorb 119FL(all four being products of Chiba Specialty Chemicals Inc.); ADK STABLA-57, ADK STAB LA-62, ADK STAB LA-67, ADK STAB LA-63 and ADK STAB LA-68(all five being products of Adeka Corporation); and Sanol LS-770, SanolLS-765, Sanol LS-292, Sanol LS-2626, Sanol LS-1114 and Sanol LS-744 (allsix being product of Sankyo Lifetech Co., Ltd.). Specific examples ofthe antioxidants are disclosed also in Japanese Kokai PublicationsH04-283259 and H09-194731.

The addition level of the antioxidant is preferably 0.1 to 10 parts byweight, and more preferably 0.2 to 5 parts by weight, per 100 parts byweight of the organic polymer (A).

In the curable composition of the present invention, there can beincorporated a light stabilizer, if necessary. By adding a lightstabilizer, the cured products obtained can be prevented from undergoingphotooxidative degradation.

The light stabilizer is not particularly restricted but includesbenzotriazole type, hindered amine type and benzoate type compounds.Among these, hindered amine type light stabilizers are preferred.

The addition level of the light stabilizer is preferably 0.1 to 10 partsby weight, and more preferably 0.2 to 5 parts by weight, per 100 partsby weight of the organic polymer (A). A specific example of the lightstabilizer is disclosed in Japanese Kokai Publication H09-194731 aswell.

When such a photocurable substance as an unsaturated acrylic compound isadded to the curable composition of the present invention, a tertiaryamine group-containing hindered amine type light stabilizer ispreferably added as disclosed in Japanese Kokai Publication H05-70531since, then, the storage stability of the curable composition isimproved.

The tertiary amine group-containing hindered amine type light stabilizeris not particularly restricted but includes Tinuvin 622LD, Tinuvin 144and Chimassorb 119FL (all three being products of Ciba SpecialtyChemicals Inc.); ADK STAB LA-57, LA-62, LA-67 and LA-63 (all four beingproducts of Adeka Corporation); and Sanol LS-765, LS-292, LS-2626,LS-1114 and LS-744 (all five being products of Sankyo Lifetech Co.,Ltd.).

To the curable composition of the present invention, there can be addedan ultraviolet absorber, if necessary. When an ultraviolet absorber isadded to the curable composition, the surface weather resistance of thecured products obtained is improved.

The ultraviolet absorber is not particularly restricted but includesbenzophenone type, benzotriazole type, salicylate type, substitutedtolyl type and metal chelate type compounds.

Among these, benzotriazole type ultraviolet absorbers are preferred.

The addition level of the ultraviolet absorber is preferably 0.1 to 10parts by weight, and more preferably 0.2 to 5 parts by weight, per 100parts by weight of the organic polymer (A).

The antioxidant, light stabilizer and ultraviolet absorber mentionedabove are preferably added in combination to the curable compositionand, for example, a phenol type or hindered phenol type antioxidant, ahindered amine type light stabilizer and a benzotriazole typeultraviolet absorber are preferably added in admixture to the curablecomposition.

An epoxy resin can be added, if necessary, to the curable composition ofthe present invention. The addition of an epoxy resin improves theadhesiveness of the obtained cured products and, therefore, the curablecomposition added with an epoxy resin is favorably used as an adhesive,and in particular, as an adhesive for outside-wall tiles.

The epoxy resin is not particularly restricted but includes, forexample, epichlorohydrin-bisphenol A-type epoxy resins,epichlorohydrin-bisphenol F-type epoxy resins, flame retardant epoxyresins such as glycidyl ethers of tetrabromobisphenol A, novolak-typeepoxy resins, hydrogenated bisphenol A-type epoxy resins, bisphenol Apropylene oxide adduct glycidyl ether-type epoxy resins, p-oxybenzoicacid glycidyl ether ester-type epoxy resins, m-aminophenol epoxy resins,diaminodiphenylmethane epoxy resins, urethane-modified epoxy resins,various alicyclic epoxy resins, N,N-diglycidylaniline,N,N-diglycidyl-o-toluidine, triglycidyl isocyanurate, polyalkyleneglycol diglycidyl ethers, glycidyl ethers of polyhydric alcohols such asglycerol, hydantoin-type epoxy resins, and epoxidized unsaturatedpolymers derived from petroleum resins or the like.

Among these, an epoxy resin having at least two epoxy groups permolecule is preferable since the reactivity of the curable compositionis enhanced and the resulting cured product easily forms athree-dimensional network structure. Bisphenol A-type epoxy resins,novolak-type epoxy resins and the like are more preferable.

The addition level of the epoxy resin depends on the application of thecurable composition, etc. For example, in order to improve impactresistance, flexibility, toughness, peel strength or the like of theepoxy resin cured product, the organic polymer (A) is added preferablyin an amount of 1 to 100 parts by weight, and more preferably in anamount of 5 to 100 parts by weight, per 100 parts by weight of the epoxyresin. On the other hand, in order to improve strength of the curedproduct of the organic component (A), the epoxy resin is addedpreferably in an amount of 1 to 200 parts by weight, and more preferablyin an amount of 5 to 100 parts by weight, per 100 parts by weight of theorganic polymer (A).

When the epoxy resin is added to the curable composition of the presentinvention, it is preferable to use a curing agent for epoxy resinstogether.

The curing agent for epoxy resins is not particularly restricted as longas it functions to cure an epoxy resin. For example, mention may be madeof primary and secondary amines such as triethylenetetramine,tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperidine,m-xylylenediamine, m-phenylenediamine, diaminodiphenylmethane,diaminodiphenylsulfone, isophoronediamine, and amine-terminatedpolyether; tertiary amines such as 2,4,6-tris(dimethylaminomethyl)phenoland tripropylamine, and salts of these tertiary amines; polyamideresins; imidazoles; dicyandiamides; boron trifluoride complex compounds;carboxylic anhydrides such as phthalic anhydride, hexahydrophthalicanhydride, tetrahydrophthalic anhydride, dodecynylsuccinic anhydride,pyromellitic anhydride, and chlorendic anhydride; alcohols; phenols;carboxylic acids; diketone complexes of aluminum or zirconium; and likecompounds. These curing agents may be used singly or a plurality thereofmay be used in combination.

The addition level of the curing agent for epoxy resins is preferably0.1 to 300 parts by weight per 100 parts by weight of the epoxy resin.

Among the curing agents for epoxy resins, a ketimine compound ispreferably used because it is possible to obtain a one-pack type curablecomposition. The ketimine compound is stable in the absence of moisture,and on the other hand, with moisture, it is decomposed into a primaryamine and a ketone. The resultant primary amine functions as a curingagent capable of curing an epoxy resin at room temperature. Suchketimine compounds include those obtained by condensation reactionbetween an amine compound and a carbonyl compound.

The amine compound and carbonyl compound used for producing the ketiminecompound are not particularly restricted but include publicly knowncompounds. Examples of the amine compound include: diamines such asethylenediamine, propylenediamine, trimethylenediamine,tetramethylenediamine, 1,3-diaminobutane, 2,3-diaminobutane,pentamethylenediamine, 2,4-diaminopentane, hexamethylenediamine,p-phenylenediamine, and p,p′-biphenylenediamine; polyvalent amines suchas 1,2,3-triaminopropane, triaminobenzene, tris(2-aminoethyl)amine, andtetrakis(aminomethyl)methane; polyalkylene polyamines such asdiethylenetriamine, triethylenetriamine, and tetraethylenepentamine;polyoxyalkylene polyamines; aminosilanes such asγ-aminopropyltriethoxysilane,N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, andN-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane; and the like.

Examples of the carbonyl compound include: aldehydes such asacetaldehyde, propionaldehyde, n-butylaldehyde, isobutylaldehyde,diethylacetaldehyde, glyoxal, and benzaldehyde; cyclic ketones such ascyclopentanone, trimethylcyclopentanone, cyclohexanone, andtrimethylcyclohexanone; aliphatic ketones such as acetone, methyl ethylketone, methyl propyl ketone, methyl isopropyl ketone, methyl isobutylketone, diethyl ketone, dipropyl ketone, diisopropyl ketone, dibutylketone, and diisobutyl ketone; β-dicarbonyl compounds such asacetylacetone, methyl acetoacetate, ethyl acetoacetate, dimethylmalonate, diethyl malonate, methyl ethyl malonate, and dibenzoylmethane;and the like.

Examples of the ketimine compound having an imino group include thoseobtained by reacting the imino group therein with: styrene oxide;glycidyl ether such as butyl glycidyl ether and allyl glycidyl ether;glycidyl ester; or the like.

Either a single species among these ketimine compounds may be added or acombination of a plurality thereof may be added.

The addition level of the ketimine compound varies according to kinds ofepoxy resins and ketimines; generally, the addition level is preferably1 to 100 parts by weight per 100 parts by weight of the epoxy resin.

To the curable composition of the present invention, there can be addeda flame retardant, if necessary. The flame retardant is not particularlyrestricted; thus, for example, phosphorus type flame retardants such asammonium polyphosphate and tricresyl phosphate; and such flameretardants as aluminum hydroxide, magnesium hydroxide and thermallyexpandable graphite can be added to the curable composition. The flameretardant to be added thereto may comprise a single species or acombination of a plurality of species.

The addition level of the flame retardant is preferably 5 to 200 partsby weight, and more preferably 10 to 100 parts by weight, per 100 partsby weight of the organic polymer.

To the curable composition of the present invention may be added, ifnecessary, various additives other than those mentioned above for thepurpose of adjusting various physical properties of the curablecomposition or of the cured products to be obtained. As such additives,there may be mentioned, for example, curability modifiers, radicalinhibitors, metal deactivators, antiozonants, phosphorus type peroxidedecomposers, lubricants, pigments, blowing agents, anti-termites andantifungal agents. Specific examples of these are disclosed inpublications such as Japanese Kokoku Publications H04-69659 andH07-108928, and Japanese Kokai Publications S63-254149, S64-22904 and2001-72854. These additives may be added singly to the curablecomposition or a plurality thereof may be added in combination to thecurable composition.

In cases where the curable composition is of the one-pack type, thecomposition contains all components as mixed up in advance and, thus,curing may proceed during storage if moisture is present in formulationcomponents. Therefore, those formulation components which containmoisture are preferably dehydrated and dried prior to addition ordehydrated during compounding and kneading by reducing the pressure, forinstance.

When the curable composition is of the two-pack type, it is notnecessary to incorporate the curing catalyst in the main componenthaving a reactive silyl group-containing organic polymer and, therefore,even if some moisture is contained in the formulation components, therisk of the progress of curing (gelation) is low; in cases wherelong-term storage stability is required, however, it is preferred thatthe formulation components be dehydrated or dried.

As for the method of dehydrating or drying, the method comprising dryingby heating and the method comprising dehydrating under reduced pressureare preferred in cases where the formulation components are solids suchas powders and, in cases where they are liquids, the vacuum dehydrationmethod and the dehydration method using a synthetic zeolite, activatedalumina, silica gel, quick lime, magnesium oxide or the like arepreferred and, further, the dehydration method comprising adding analkoxysilane compound such as n-propyltrimethoxysilane,vinyltrimethoxysilane, vinylmethyldimethoxysilane, methyl silicate,ethyl silicate, γ-mercpatopropylmethyldimethoxysilane,γ-mercaptopropylmethyldiethoxysilane andγ-glycidoxypropyltrimethoxysilane; an oxazolidine compound such as3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine; or an isocyanatecompound to the curable composition and allowing the same to react withwater contained in the formulation components is also preferred. In thisway, the storage stability of the curable composition is improved by theaddition of such an alkoxysilane compound, oxazolidine compound orisocyanate compound.

In using vinyltrimethoxysilane or a like alkoxysilane compound capableof reacting with water for the purpose of drying, the addition levelthereof is preferably O. 1 to 20 parts by weight, and more preferably0.5 to 10 parts by weight, per 100 parts by weight of the organicpolymer (A).

The method of preparing the curable composition of the present inventionis not particularly restricted but there may be employed, for example,such a method known in the art as a method comprising combining theformulation components mentioned above and kneading the resultingmixture at ordinary temperature or with heating using a mixer, roller,kneader, or the like, or a method comprising dissolving the formulationcomponents using small portions of an appropriate solvent and thenmixing up the solutions.

When exposed to the air, the curable composition of the presentinvention forms a three-dimensional network structure under the actionof atmospheric moisture and thus is cured to give a solid having rubberelasticity.

The curable composition of the present invention can be suitably used insuch fields of application as pressure-sensitive adhesives; sealants forbuildings, ships, automobiles, roads, etc.; adhesives; impressionmaterials; vibration-proof materials; damping materials; soundproofmaterials; expanded/foamed materials; coating compositions; spraycoatings, etc. Among such fields of application, the use as sealants oradhesives is more preferred since the cured products obtained areexcellent in flexibility and adhesiveness.

The curable composition of the present invention can also be used insuch various fields of application as back cover sealants for a solarcell and like electric and electronic part materials; insulating covermaterials for electric wires and cables and other electric insulatingmaterials; elastic adhesives; contact adhesives; spray sealants; crackrepair materials; tiling adhesives; powder coating compositions; castingmaterials; rubber materials for medical use; pressure-sensitiveadhesives for medical use; sealants for medical devices; food packagingmaterials; joint sealants for siding boards and other exteriormaterials; coating materials; primers; electromagnetic wave shieldingconductive materials, thermally conductive materials; hot meltmaterials; potting agents for electrics and electronics; films; gaskets;various molding materials; rustproof and waterproof sealants for wiredglass and laminated-glass edges (cut end faces); liquid sealants for usein automotive parts, electrical machinery parts, various machineryparts, etc.

Further, the curable composition can also be used as various types ofhermetically sealants and adhesives since it, either alone or with theaid of a primer, can adhere to a wide range of substrates such as glass,ceramics, wood, metals and resin moldings.

The curable composition of the present invention can also be used in theform of interior panel adhesives, exterior panel adhesives, tilingadhesives, stone pitching adhesives, ceiling finishing adhesives, floorfinishing adhesives, wall finishing adhesives, vehicle panel adhesives,electric, electronic and precision apparatus assembling adhesives,direct glazing sealants, double glazing sealants, sealants for SSGsystems, or building working joint sealants.

EXAMPLES

The following examples and comparative examples illustrate the presentinvention more specifically. These are, however, by no means limitativeof the scope of the present invention.

Synthesis Example 1

Propylene oxide was polymerized using a 1/1 (in weight ratio) mixture ofpolyoxypropylene diol with a molecular weight of about 2,000 andpolyoxypropylene triol with a molecular weight of about 3,000 as aninitiator and a zinc hexacyanocobaltate glyme complex catalyst to givepolypropylene oxide having a number average molecular weight of about19,000 (polystyrene-equivalent molecular weight measured by using aTOSOH model HLC-8120 GPC solvent delivery system and a TOSOH modelTSK-GEL H type column, with THF as a solvent). Thereto was then added amethanol solution of NaOMe in an amount of 1.2 equivalents relative tothe hydroxyl groups of that hydroxyl-terminated polypropylene oxide, themethanol was distilled off and, further, allyl chloride was added to theresidue for conversion of each terminal hydroxyl group to an allylgroup. In the above manner, allyl group-terminated polypropylene oxidewith a number average molecular weight of about 19,000 was obtained.

To 100 parts by weight of the crude allyl group-terminated polypropyleneoxide obtained were added 300 parts by weight of n-hexane and 300 partsby weight of water and, after mixing with stirring, the water wasremoved by centrifugation. The hexane solution obtained was furthermixed with 300 parts by weight of water with stirring, and after thewater was removed again by centrifugation, the hexane was removed byvolatilization under reduced pressure to give purified allylgroup-terminated polypropylene oxide (hereinafter, referred to as an“allyl polymer”). The obtained allyl polymer (100 parts by weight) wasreacted with 1.35 parts by weight of methyldimethoxysilane at 90° C. for5 hours by adding 150 ppm of an isopropanol solution of aplatinum-vinylsiloxane complex (platinum content: 3% by weight) theretoas a catalyst to give a methyldimethoxysilyl group-terminatedpolypropylene oxide (A-1). As a result of ¹H-NMR measurement (made inCDCl₃ solvent using a Nippon Denshi (JEOL Ltd.) model JNM-LA400), theaverage number of terminal methyldimethoxysilyl groups per molecule wasfound to be about 1.7.

Synthesis Example 2

Propylene oxide was polymerized using polyoxypropylene triol with amolecular weight of about 3,000 as an initiator and a zinchexacyanocobaltate glyme complex catalyst to give polypropylene oxide(P-2) having a number average molecular weight of about 26,000(polystyrene-equivalent molecular weight measured by using the samemethod as in Synthesis Example 1). Thereto was then added a methanolsolution of NaOMe in an amount of 1.2 equivalents relative to thehydroxyl groups of the hydroxyl-terminated polypropylene oxide, themethanol was distilled off and, further, allyl chloride was added to theresidue for conversion of each terminal hydroxyl group to an allylgroup. The unreacted allyl chloride was removed by volatilization underreduced pressure. To 100 parts by weight of the crude allylgroup-terminated polypropylene triol obtained were added 300 parts byweight of n-hexane and 300 parts by weight of water and, after mixingwith stirring, the water was removed by centrifugation. The hexanesolution obtained was further mixed with 300 parts by weight of waterwith stirring, and after the water was removed again by centrifugation,the hexane was removed by volatilization under reduced pressure. In theabove manner, the allyl group-terminated trifunctional polypropyleneoxide (P-3) with a number average molecular weight of about 26,000 wasobtained. Into a 1 L autoclave were introduced 100 parts by weight ofthe allyl group-terminated trifunctional polypropylene oxide obtainedand 2 parts by weight of hexane, the mixture was subjected to azeotropicdehydration at 90° C., hexane was distilled off under reduced pressure,and thereafter nitrogen substitution was performed. The obtained productwas reacted with 1.28 parts by weight of trimethoxysilane at 90° C. for5 hours by adding 150 ppm of an isopropanol solution of aplatinum-divinyldisiloxane complex (platinum content: 3% by weight)thereto as a catalyst to give a terminated polyoxypropylene polymer(A-2). As a result of the same ¹H-NMR measurement as above, the averagenumber of terminal trimethoxysilyl groups per molecule was found to be1.8

Synthesis Example 3

To polyoxypropylene triol with a molecular weight of about 3,000 wasadded a methanol solution of NaOMe in an amount of 1.2 equivalents, themethanol was distilled off and, further, allyl chloride was added toconvert the terminal hydroxyl groups to allyl groups. The unreactedallyl chloride was removed by volatilization under reduced pressure togive an allyl group-terminated polypropylene glycol.

Mix Example 1

To 8 parts by weight of 1-(o-tolyl)biguanide (product of Ouchi ShinkoChemical Industrial Co., Ltd., trade name: Nocceler BG) was added 16parts by weight of N-n-butyl benzene sulfonamide (product of Fuji AmideChemical Co., Ltd., trade name: Top Sizer No. 7) and sufficientlystirred to give a white turbid liquid. Thereto was added 4 parts byweight of γ-aminopropyltrimethoxysilane (product of Dow Corning TorayCo., Ltd., trade name: A-1110). After mixing up and 30 minutes ofstanding in an oven at 80° C., a colorless and transparent liquid(mixture A) was obtained.

Mix Example 2

To 8 parts by weight of 1-(o-tolyl)biguanide were added 16 parts byweight of tetrahydrothiophene-1,1-dioxide (product of New Japan ChemicalCo., Ltd., trade name: anhydrous sulfolane) and 4 parts by weight ofγ-aminopropyltrimethoxysilane. After mixing up and 30 minutes ofstanding in an oven at 80° C., a colorless and transparent liquid(mixture B) was obtained.

Mix Example 3

To 6 parts by weight of 1-phenylguanidine (product of Nippon CarbideIndustries Co., Inc.) was added 12 parts by weight of N-n-butyl benzenesulfonamide and sufficiently stirred to give a yellow turbid liquid.Thereto was added 3 parts by weight of γ-aminopropyltrimethoxysilane.After mixing up and 30 minutes of standing in an oven at 80° C., ayellow and transparent liquid (mixture C) was obtained.

Mix Example 4

To 6 parts by weight of 1-phenylguanidine were added 12 parts by weightof tetrahydrothiophene-1,1-dioxide and 3 parts by weight ofγ-aminopropyltrimethoxysilane. After mixing up and 30 minutes ofstanding in an oven at 80° C., a yellow and transparent liquid (mixtureD) was obtained.

Mix Example 5

To 8 parts by weight of 1-(o-tolyl)biguanide was added 16 parts byweight of methyl ethyl ketone (product of Wako Pure Chemical Industries,Ltd., reagent). After mixing up, a colorless and transparent liquid(mixture E) was obtained.

Mix Example 6

To 8 parts by weight of 1-(o-tolyl)biguanide was added 16 parts byweight of ethanol (product of Wako Pure Chemical Industries, Ltd.,reagent). After mixing up, a colorless and transparent liquid (mixtureF) was obtained.

Mix Example 7

To 8 parts by weight of 1-(o-tolyl)biguanide was added 16 parts byweight of polyoxypropylene diol with a molecular weight of 3,000(product of Mitsui Takeda Chemicals, trade name: Actcol P-23). Aftermixing up and 30 minutes of standing in an oven at 80° C., a whiteturbid liquid (mixture G), not a transparent liquid, was obtained. Afterleaving at room temperature, a white precipitate occurred.

Example 1

Surface-treated colloidal calcium carbonate (120 parts by weight;product of Shiraishi Kogyo, trade name: Hakuenka CCR), 39 parts byweight of a polypropylene glycol type plasticizer with a molecularweight of 3,000 (product of Mitsui Takeda Chemicals, trade name: ActcolP-23), 20 parts by weight of titanium oxide (white pigment) (product ofIshihara Sangyo, trade name: Tipaque R-820), 2 parts by weight of anantisagging agent (product of Kusumoto Chemicals Ltd., trade name:Disparlon 6500), 1 part by weight of a benzotriazole type ultravioletabsorber (product of Ciba Specialty Chemicals, trade name: Tinuvin 326)and 1 part by weight of a hindered amine type light stabilizer (productof Sankyo Lifetech, trade name: Sanol LS-770) were weighed and admixedwith 50 parts by weight of the methyldimethoxysilyl group-terminatedpolyoxypropylene polymer (A-1) obtained in Synthesis Example 1 and 50parts by weight of the trimethoxysilyl group-terminated polyoxypropylenepolymer (A-2) obtained in Synthesis Example 2, and, after thoroughkneading, the mixture was passed through a three-roll paint mill threetimes for dispersion. Thereafter, the mixture was dehydrated at 120° C.for 2 hours under reduced pressure and, after cooling to a temperaturenot higher than 50° C., 2 parts by weight of vinyltrimethoxysilane(product of Dow Corning Toray Co., Ltd., trade name: A-171) as adehydrating agent, and 28 parts by weight of the mixture A obtained inMix Example 1 were added and kneaded. After kneading under substantiallywater-free conditions, the resulting mixture was hermetically packed ina cartridge that is a moisture-proof container. A one-pack type curablecomposition was thus obtained.

Example 2

A curable composition was obtained in the same method as in Example 1except that 3 parts by weight of oleyl monoglyceride (product of KaoCorporation, trade name: Excel O-95R) was further added to the curablecomposition obtained according to Example 1.

Example 3

A curable composition was obtained in the same method as in Example 1except that the allyl group-terminated polypropylene glycol obtained inSynthesis Example 3 was used in lieu of the polypropylene glycol typeplasticizer used in Example 1.

Example 4

A curable composition was obtained in the same method as in Example 1except that the mixture B obtained in Mix Example 2 was used in lieu ofthe mixture A used in Example 1.

Example 5

A curable composition was obtained in the same method as in Example 3except that the mixture B obtained in Mix Example 2 was used in lieu ofthe mixture A used in Example 3.

Example 6

A curable composition was obtained in the same method as in Example 1except that the polymer (A-1) was used in an amount of 80 parts byweight, the polymer (A-2) was used in an amount of 20 parts by weight,and the polypropylene glycol type plasticizer was used in an amount of43 parts by weight, and further, 21 parts by weight of the mixture Cobtained in Mix Example 3 was used in lieu of the mixture A used inExample 1.

Example 7

A curable composition was obtained in the same method as in Example 6except that the mixture D obtained in Mix Example 4 was used in lieu ofthe mixture C used in Example 6.

Comparative Example 1

A curable composition was obtained in the same method as in Example 1except that the propylene glycol type plasticizer was used in an amountof 55 parts by weight, and 4 parts by weight ofγ-aminopropyltrimethoxysilane (product of Dow Corning Toray Co., Ltd.,trade name: A-1110) and 8 parts by weight of 1-(o-tolyl)biguanide in apowder state were used in lieu of addition of the mixture A.

Comparative Example 2

A curable composition was obtained in the same method as in Example 1except that 4 parts by weight of γ-aminopropyltrimethoxysilane and 24parts by weight of the mixture E obtained in Mix Example 5 were used inlieu of addition of the mixture A in Example 1.

Comparative Example 3

A curable composition was obtained in the same method as in ComparativeExample 2 except that the mixture F obtained in Mix Example 6 was usedin lieu of the mixture E used in Comparative Example 2.

Comparative Example 4

A curable composition was obtained in the same method as in ComparativeExample 1 except that the polymer (A-2) was not used, and the polymer(A-1) was used in an amount of 100 parts by weight.

Comparative Example 5

A curable composition was obtained in the same method as in ComparativeExample 2 except that the polymer (A-2) was not used, and the polymer(A-1) was used in an amount of 100 parts by weight.

Comparative Example 6

A curable composition was obtained in the same method as in ComparativeExample 5 except that the mixture G obtained in Mix Example 7 was usedin lieu of the mixture E used in Comparative Example 5. The mixture Ghad a white solid precipitated therein, but the mixture G which had beenstirred immediately before use thereof to be in a uniform state wasused.

The surface cure time, surface cure time after storage, depthcurability, cured product tensile properties, initial viscosity,viscosity after storage, surface states after smoothing the surface, andodors of curable compositions were evaluated on one-pack typemoisture-curable compositions obtained in Examples 1 to 7 andComparative Examples 1 to 6, based on the following methods. The resultsobtained are shown in Table 1. “After storage” as used herein refers to28 days of standing of a container containing the one-pack typemoisture-curable composition in an oven at 50° C. Thereafter, afterleaving under conditions of 23° C. and 50% RH for not less than 24hours, each of the evaluations was made on the same conditions as forthe one-pack type moisture-curable composition in the initial state.

(Surface Cure Time)

Under conditions of 23° C. and 50% RH, each of the above curablecompositions was spread to a thickness of about 3 mm with a spatula, andthe surface of the curable composition was touched gently with amicrospatula from time to time and the time required for the compositionto become no more sticking to the microspatula was determined.

(Depth curability)

Under conditions of 23° C. and 50% RH, each of the above curablecompositions was packed into a polyethylene tube with a diameter of 12mm without allowing entrance of bubbles, and the excess was scraped awaywith a spatula to make the surface level, giving a test sample.

The test sample was allowed to leave under the same conditions for 7days, the cured surface layer portion was then stripped off and, afterremoving the uncured portion thoroughly, the thickness of the curedportion was measured using vernier calipers.

(Cured Product Tensile Properties)

A 3-mm-thick sheet-shaped test sample was prepared from each of theabove curable compositions, and then, set and cured by allowing the testsample to leave under conditions of 23° C. and 50% RH for 3 days andfurther at 50° C. for 4 days. No. 3 dumbbell specimens were punched outfrom the sheet and subjected to tensile testing using a Shimadzu modelautograph at a pulling rate of 200 mm/minute, and the 100% tensilemodulus, strength at break and elongation at break were measured.

(Viscosity)

Each of the above curable compositions was packed in a 100-cc cup so asto prevent air from entering the cup, and the viscosities at 2 rpm weremeasured using a BS type viscometer and a rotor No. 7 (products of TokyoKeiki Inc.) under conditions of 23° C. and 50% RH.

(Surface State After Smoothing Surface)

Using a spatula, each of the above curable compositions was smoothed soas to have a thickness of about 3 mm, and the surface state was observedby eye.

(Odor of Curable Composition)

About 50 g of each of the above curable compositions was taken out ofthe container, and odors thereof were smelled.

TABLE 1 Examples 1 2 3 4 5 6 7 Silyl group-containing A-1 50 50 50 50 5080 80 organio polymer A-2 50 50 50 50 50 20 20 Calcium carbonateHakuenka CCR 120 120 120 120 120 120 120 Plasticizer Actool P-23 39 3839 43 43 Allyl group-terminated 39 39 polypropylene glycol PigmentTipaque R-820 20 20 20 20 20 20 20 Antisagging agent Disparion 6500 2 22 2 2 2 2 Physical property modifier Excel O-95R 3 Ultraviolet absorberTinuvin 326 1 1 1 1 1 1 1 Light stabillzer Sanol LS-770 1 1 1 1 1 1 1Dehydrating agent Vinyltrimethoxysilane 2 2 2 2 2 2 2Adhesiveness-imparting γ-Aminopropyltrimethoxysilane agent Mixture A 2828 28 Mixture B 28 28 Mixture C 21 Mixture D 21 Mixture E Mixture FMixture G 1-(o-Tolyl)biguanide Surface cure time (min) 40 40 35 40 35 3530 Surface cure time after storage (min) 30 30 25 35 30 30 25 Depthcurability (mm) 10.2 11.1 10.4 12.1 11.6 9.1 11.2 Cured product tensile100% modulus (MPa) 0.59 0.58 0.67 0.84 0.71 0.67 0.77 propertiesStrength at break (MPa) 2.01 1.95 2.25 2.18 2.29 1.99 2.45 Elongation atbreak (%) 505 590 535 585 490 545 585 Initial viscosity (Pa · a) 14301585 1600 1480 1360 1200 1335 Viscosity after storage (Pa · s) 2730 27502820 2625 1760 2320 2565 Thickening rate 1.9 1.7 1.8 1.8 1.3 1.9 1.9Surface state after smoothing surface smooth smooth smooth smooth smoothsmooth smooth Odor of curable composition no odor no odor no odor noodor no odor no odor no odor Comparative Examples 1 2 3 4 5 6 Silylgroup-containing A-1 50 50 50 100 100 100 organio polymer A-2 50 50 50 00 0 Calcium carbonate Hakuenka CCR 120 120 120 120 120 120 PlasticizerActool P-23 55 39 39 55 39 39 Allyl group-terminated polypropyleneglycol Pigment Tipaque R-820 20 20 20 20 20 20 Antisagging agentDisparion 6500 2 2 2 2 2 2 Physical property modifier Excel O-95RUltraviolet absorber Tinuvin 326 1 1 1 1 1 1 Light stabillzer SanolLS-770 1 1 1 1 1 1 Dehydrating agent Vinyltrimethoxysilane 2 2 2 2 2 2Adhesiveness-imparting γ-Aminopropyltrimethoxysilane 4 4 4 4 4 4 agentMixture A Mixture B Mixture C Mixture D Mixture E 24 24 Mixture F 24Mixture G 24 1-(o-Tolyl)biguanide 8 8 Surface cure time (min) 40 35 18010 hours 10 hours 10 hours or more or more or more Surface cure timeafter storage (min) 35 30 480 10 hours 10 hours 10 hours or more or moreor more Depth curability (mm) 10.4 10.3 9.8 8.5 5.8 6.9 Cured producttensile 100% modulus (MPa) 0.62 0.85 0.53 0.58 0.58 0.59 propertiesStrength at break (MPa) 1.88 2.00 1.89 1.93 2.10 2.22 Elongation atbreak (%) 460 500 650 520 605 630 Initial viscosity (Pa · a) 1200 10801110 1465 1170 1720 Viscosity after storage (Pa · s) 1956 2340 2295 27851980 4760 Thickening rate 1.6 2.2 2.1 1.9 1.7 2.8 Surface state aftersmoothing surface small smooth smooth small smooth smooth mass massobserved observed Odor of curable composition no odor aceton alcohol noodor aceton no odor odor odor odor

Table 1 clearly indicates that in Examples 1 to 7 in which the amidinecompound was dissolved in the sulfonyl group-containing compound andthen added, surface curing and depth curing were rapid, and the curedproduct exhibited favorable tensile properties: high strength and highelongation. Further, the rise in viscosity after storage was not greatbut favorable, and no agglomeration of the amidine compound wasobserved. On the other hand, in Comparative Example 1 and ComparativeExample 4 in which the amidine was added as a powder, when the curablecomposition was smoothed, a small mass was observed on the surface, andthe strength and elongation of the cured product were not sufficient. InComparative Example 2 and Comparative Example 5 in which the amidinecompound was dissolved in methyl ethyl ketone and then added, althoughthe dispersibility of the amidine compound was favorable, acetone odorwas emitted, which means that room environment may be deteriorated whenused in a room. In Comparative Example 3 in which the amidine compoundwas dissolved in ethanol and added, although the dispersibility of theamidine compound was favorable, alcohol odor was emitted. In addition,the surface curability and depth curability were slow. In ComparativeExample 6, an attempt was made to dissolve the amidine compound inpolypropylene glycol, but the amidine compound was not dissolved even byheating and, after leaving at room temperature, a white precipitateoccurred, which deteriorated workability thereof. The curablecomposition using this also showed a significant rise in viscosity afterstorage and poor viscosity stability.

1. A curable composition which comprises: 100 parts by weight of anorganic polymer (A) containing, in a molecule, a reactive silyl grouprepresented by the formula: —SiR¹ _(n)X¹ _(3-n) (wherein the n R¹ groupseach represent at least one kind selected from the group consisting ofC₁₋₂₀ alkyl groups, C₆₋₂₀ aryl groups and C₇₋₂₀ aralkyl groups, and the(3-n) X¹s are each independently either a hydroxyl group or ahydrolyzable group); 0.1 to 30 parts by weight of an amidine compound(B) represented by the formula (1):R²N═CR³—NR⁴ ₂   (1) (wherein R², R³, and the two R⁴s are eachindependently a hydrogen atom or an organic group); and 0.1 to 100 partsby weight of a compound (C) containing, in a molecule, a sulfonyl grouprepresented by the formula: —S(═O)₂—.
 2. The curable compositionaccording to claim 1, wherein the amidine compound (B) is dissolvedand/or dispersed in the sulfonyl group-containing compound (C), and theresultant product is mixed in the reactive silyl group-containingorganic polymer (A).
 3. A curable composition which comprises: areactive silyl group-containing organic polymer (A); an amidine compound(B); a sulfonyl group-containing compound (C); and a silane couplingagent (D).
 4. The curable composition according to claim 3, wherein theamidine compound (B) is dissolved and/or dispersed in the sulfonylgroup-containing compound (C) and the silane coupling agent (D), and theresultant product is mixed in the reactive silyl group-containingorganic polymer (A).
 5. The curable composition according to claim 3,wherein the amidine compound (B) is dissolved and/or dispersed in thesulfonyl group-containing compound (C), thereafter, the silane couplingagent (D) is added to the resultant mixture, and dissolved and/ordispersed, and the resultant product is mixed in the reactive silylgroup-containing organic polymer (A).
 6. The curable compositionaccording to claim 4, wherein the silane coupling agent (D) contains anamino group in a molecule.
 7. The curable composition according to claim1, wherein the main chain skeleton of the reactive silylgroup-containing organic polymer (A) is a polyoxyalkylene and/or(meth)acrylate ester polymer.
 8. The curable composition according toclaim 1, wherein the amidine compound (B) represented by the formula (1)is a guanidine compound in which R³ in the formula (1) is an organicgroup represented by —NR⁵ ₂ (wherein the two R⁵s are each independentlyan organic group).
 9. The curable composition according to claim 1,wherein the amidine compound (B) contains an aryl group in a molecule.10. The curable composition according to claim 1, wherein the sulfonylgroup-containing compound (C) has a boiling point of not lower than 200°C. at 760 mmHg.
 11. The curable composition according to claim 1,wherein 3 to 100% by weight of the reactive silyl group contained in onemolecule of the reactive silyl group-containing organic polymer (A) is asilyl group represented by the formula: —SiX¹ ₃ (wherein the three X¹sare each independently either a hydroxyl group or a hydrolyzable group).12. A sealant which comprises the curable composition according toclaim
 1. 13. An adhesive which comprises the curable compositionaccording to claim
 1. 14. The curable composition according to claim 4,wherein the main chain skeleton of the reactive silyl group-containingorganic polymer (A) is a polyoxyalkylene and/or (meth)acrylate esterpolymer.